What can ethnic differences tell us about the desiring gaze while addressing the motives that result from the power and desire in gay ethnic pornography in Europe? How do pornographic films authenticate their ethnic subject in different European countries and how can the fetishism of presenting an authentically foreign body be best approached? Is the transformation of sex tourism, which affects countries differently, reflected through the ever-evolving history of gay pornography in Europe? And how does this transformation contrast or overlap with the legacies of Orientalism and colonialism? In addressing these questions, this book will participate in ongoing debates concerning Orientalism and colonialism, and make a contribution to the growing field of pornography studies. While recent works by scholars have considered the relation between US mainstream gay pornography and its representations of ethnicity and ‘race,’ and have also discussed examples from Europe (predominantly France), no historical study has yet bridged the gap between earlier European gay ethnic pornography and its current, specifically German-Turkish manifestations. Furthermore, this exploration of recent studios like GayHeim will also contribute to discussions on the mobility issues of non-European men, while illustrating how these new productions can be refugee—or migrant—positive while simultaneously perpetuating Orientalism.
Weniger anzeigenThis thesis focused on the semiochemicals mediating host-searching behavior of the ectoparasitoid Holepyris sylvanidis (Hymenoptera: Bethylidae) which attacks larvae of various stored-product pest beetles, especially those of the confused flour beetle, Tribolium confusum (Coleoptera: Tenebrionidae). Prior to this thesis, it was already known that the parasitoid uses host-specific compounds released from larval feces of T. confusum for host location and that the attractiveness of host-specific kairomones for the parasitoid increases by the addition of habitat background odor. Moreover, host cuticular hydrocarbons (CHCs) serve as contact kairomones for host recognition by H. sylvanidis and mediate trail-following behavior in foraging parasitoids, but only for a period of two days. Despite these initial findings, many chemical and ecological aspects of the parasitoid’s host search and the potential of host-specific kairomones to enhance biological control were still poorly understood. Therefore, the goal of this thesis was to gain deeper insights in the chemically mediating host search of H. sylvanidis. Various behavioral bioassays and chemical analysis of host kairomones via coupled gas chromatography-mass spectrometry were performed to answer the following questions: (i) Which factors drive the loss of kairomonal activity of host larval CHC trails over time? (Chapter 2) (ii) Do H. sylvanidis females discriminate a host from a non-host species based on a host-specific CHC pattern present on the cuticle? (Chapter 3) (iii) Does the additional application of host-specific kairomones improve the host search activity of the parasitoid and thus, its efficiency in controlling T. confusum? (Chapter 4). In Chapter 2, we first investigated whether the time-limited kairomonal activity of host trails was due to changes in the CHC composition induced by microbes. Chemical analysis revealed that the CHC profile of host trails did not change qualitatively or quantitatively over a two-day period regardless of whether they were analyzed under sterile or non-sterile conditions. These results prompted the suggestion that factors other than microbial degradation might determine the temporary behavioral activity of CHC trails. This assumption was confirmed by our cryo-scanning electron microcopy results. Within two days, host trails gradually formed solid microstructures most likely due to a self-assembly of CHCs. But this process was reversible by hexane application which in turn led to the recovery of kairomonal activity of two-day-old CHC trails. Parasitoids followed these re-activated host trails as they did when encountering freshly laid ones. Our results suggest that the gradual solidification of long-chain CHCs in a host trail over time reduces the perceptibility for H. sylvanidis as such that the trail is no longer followed. In Chapter 3 we examined the influence of different CHC profiles of three closely related and one distantly related beetle species on the host recognition behavior of H. sylvanidis. In bioassays the parasitoid successfully recognized and accepted larvae of Tribolium spp. as hosts, whereas larvae of Oryzaephilus surinamensis were rejected. The latter species elicited a behavioral response in H. sylvanidis only when solvent extracted larvae were treated with a sample of T. confusum larval CHCs. Chemical analysis of larval extracts showed that the CHC profiles of the host and non-host species differed in their compositions. The main difference was the presence of methylated alkanes (MeAL) on the cuticle of Tribolium spp. and the absence of MeAL on that of O. surinamensis. MeAL serve as host recognition cues that enable the parasitoid to distinguish a host from a non-host species. In Chapter 4, we first examined whether volatiles associated either to T. confusum larvae or to other host stages (e.g., beetle adults) participate in the host search of H. sylvanidis over long distances. The parasitoid was most attracted to a mix of two larval key compounds (2CM = (E)-2-nonenal and 1-pentadecene) emitted from larval feces, but the behavioral response of the parasitoid was concentration dependent. In contrast, volatiles released by T. confusum adults were not attractive for the parasitoid in all concentrations tested. We then studied whether the additional presence of synthetic 2CM (in the most attractive concentration) has an enhancing effect on the host search of H. sylvanidis. In three-day lasting flight cage experiment we offered T. confusum larvae either with additionally applied 2CM (test) or without (control) to parasitoid females. In test cages, parasitoids removed significantly more beetle larvae from the initial population within 48 h and parasitized a significantly higher number of host larvae after 72 h compared to those in the control cages. Furthermore, significantly more parasitoid offspring emerged from host larvae parasitized in the presence of 2CM. However, the increasing population size in the F1 was due to a significant increase in male offspring. These results illustrate that the host-finding success and parasitization rate of parasitoids can be improved by the additional release of host-specific, synthetic kairomones. But this is associated with changes in the population composition (male/female) of the parasitoid progeny. Overall, the results obtained in this thesis on the semiochemicals mediating host-searching behavior of a natural antagonist of stored-product pest beetles contribute to a better understanding of the interaction between parasitoids and their host species. In addition, they provide important insights into the potential use of host-associated, behaviorally modifying compounds to increase the efficiency of parasitoids in the biological control of insect pests in storage environments.
Weniger anzeigenIn this thesis, we are dealing with prosodic language contact between the languages Vietnamese and French. This pair of languages is interesting in that both languages are prosodically very different and have very interesting prosodic properties individually. While in Vietnamese each syllable is assigned a lexical tone, French is not a lexical tone language. On the other hand, French has consonant clusters and a larger coda consonant inventory than Vietnamese. Regarding syllable structures, both languages are typologically atypical, in different respects. Our research is devoted to different language contact situations as well as to both directions of language contact. The starting point of our experimental research is the observation of French loanwords in Vietnamese. In this context, we examine prosodic adaptation patterns that speakers have undertaken to adapt the loanwords to Vietnamese. The focus is on the repair of structures that are illicit in Vietnamese: consonants in certain positions in the syllable are replaced or deleted, consonant clusters are dissolved by epenthesis or by deletion of one of the two consonants, syllable boundaries are shifted, consonants or consonant slots in certain syllabic structures are doubled, and tones are assigned to syllables according to certain patterns. The aim of our experimental investigations then is to find out whether similar or different patterns occur in an instantaneous situation of language contact. Monolingual speakers of Vietnamese are exposed to French stimuli and asked to reproduce them in three different conditions. We have additionally conducted the same experiment with learners of French whose first language is Vietnamese. The experimental data show many similar patterns to the loanword data. However, the data from monolingual speakers in particular display much more variability. Finally, we reverse the direction of language contact: native speakers of French are asked to reproduce Vietnamese stimuli. In this case, the question is whether certain patterns can be reversed in the opposite direction, which can partly be observed. With the help of the present work, we can gain a deep understanding of systematicity and variability in borrowing and second language acquisition. We conclude that from a phonological perspective, there are many similarities between the two fields of prosodic language contact, and we suggest, for the phenomena under consideration, to understand some aspects in their complexity in a gradual rather than a categorical way.
Weniger anzeigenIn the Solar System, the saturnian moon Enceladus and the jovian moon Europa are potentially habitable and the most promising candidates for space missions searching for extraterrestrial life. The subsurface oceans of these moons constitute the long-lived presence of large amounts of liquid water, a common component of icy moons throughout the outer Solar System. In addition, the rocky seafloors of both moons allow for rich geochemistry in their subsurface oceans, potentially including the formation of complex organic material at hydrothermal vent systems, which could also provide an energy source for another emergence of life. The exploration of icy ocean moons can be performed using impact ionization mass spectrometry, a powerful technique to thoroughly analyse the composition of ice grains ejected from both the surface ice shell and subsurface liquid reservoirs. The Cosmic Dust Analyzer (CDA) onboard the Cassini mission detected a variety of salts, complex and reactive organic compounds, as well as bioessential elements in ice grains ejected by the plume of Enceladus into space. CDA mass spectra provided strong evidence for habitable conditions at the seafloor of the moon. These discoveries greatly benefitted from laboratory analogue mass spectra complementing the CDA data, obtained from a laboratory setup using Laser Induced Liquid Beam Ion Desorption (LILBID) as an ionisation source coupled to time-of-flight mass spectrometry. CDA paved the way for the SUrface Dust Analyzer (SUDA), its improved successor instrument onboard the upcoming Europa Clipper mission, which will provide a deeper understanding of Europa’s habitability. SUDA aims to characterize the composition of the subsurface ocean or liquid inclusions in the icy crust by analysing young endogenic surface material or possible cryovolcanic plume material. Preparation for SUDA’s mission and related data analysis requires considerable laboratory work. This thesis describes LILBID experiments simulating the mass spectral signatures of both salt- and organic-rich ices, as expected to be encountered by SUDA or similar instruments on a future mission to Enceladus. After a description of the current state of research into the habitability and astrobiological potential of both Europa and Enceladus in Part I, Part II details how SUDA-type instruments could detect organic molecules embedded in salt-rich ice grains. LILBID mass spectra were recorded for several organic species with various properties, derived from a range of functional groups, together with either NaCl, MgSO4 or H2SO4 at concentrations relevant for the surfaces of icy moons. Mass spectrometric signatures of the organic species can be detected via their molecular ions and a range of cluster species with Na+, Mg2+, Cl−, OH−, HSO4− ions, and NaCl, MgSO4 and H2SO4 molecules. The presence and intensity of these characteristic organic-rich peaks depends on the inorganic matrix and its concentration. The intensities of analyte signatures decrease with increasing salt concentrations due to suppression effects. In contrast, they are increased by the presence of sulfuric acid matrices in cation mode. Moreover, the sensitivity to different organic species strongly depends on the instrument polarity (cation or anion mode of the spectrometer) and on molecular properties, especially the functional groups present. The recorded spectra are an important foundation to characterise both the organic and salt composition in ice grains from Europa and Enceladus and, by extension, potential constituents of the subsurface oceans. Part III reveals a previously unknown capability of SUDA-type instruments: the ability to determine the oxidation state of iron in iron-bearing salts (or other minerals) embedded in ice grains. Such analytical capability may, in the near future, allow the elucidation of key parameters related to the geochemistry of subsurface oceans on icy moons, notably their redox chemistry and pH. These factors may have implications for hydrothermal mineralogy as well as possible metabolic activity of putative microbial life. Further ongoing projects that have been conducted in the framework of this PhD project are briefly described in Part IV. They cover the irradiation of (i) icy samples containing molecular biosignatures to evaluate their degradation under the harsh radiation environment of Europa’s surface, and (ii) simple compounds (CH3OH:NH3:H2O ice) leading to the synthesis of a variety of complex organic structures. Moreover, an outlook is given on a future expedition to acquire samples in Antarctica - the best icy moon analogue on Earth - that has been planned during this PhD project. Finally, this work concludes with a summary of the most relevant results of this thesis (Part V).
Weniger anzeigenHigh-mountain landscapes are becoming increasingly dynamic under climate change, with environmental changes impacting ecosystems and societies in and near mountains. The mountain cryosphere responds to rising atmospheric temperatures with declining snow and ice cover and thawing permafrost. The snow and ice cover decline modifies the surface energy balance, allowing increased heat transfer from the atmosphere into the ground and affecting mountain permafrost. Coupled with reduced mechanical ice support by retreating glaciers, high mountain landscapes destabilise and respond with increased bedrock erosion and sediment production. Mountain glaciers become increasingly covered by supraglacial debris of variable thickness that modifies their response to climate change by altered melt rates. Observations of increased rockfall activity, catastrophic slope failures, and cascading hazards related to climate change highlight the need for large-scale monitoring and detection techniques to analyse recent landscape changes and identify regions at risk of warming-related natural hazards. In this thesis, I evaluate the potential and limitations of thermal infrared remote sensing to detect and analyse glacial landscape dynamics based on land surface temperature (LST) observations acquired from an unpiloted aerial vehicle (UAV) and multidecadal time series (1984-2022) of combined Landsat sensors. In the first study, I measured a significant portion of the diurnal temperature cycle of a debris-covered glacier section in Switzerland using UAV-acquired very high-resolution LST data and estimated spatially distributed debris thickness using two distinct approaches. The results showed that the nonlinearity in the relationship between LST and debris thickness varies throughout the day, which is relevant for interpreting satellite-derived debris thickness estimates at fixed acquisition times. Sub-daily LST measurements further allow quantifying surface energy balance components that satellite-based approaches cannot capture. Consequently, UAV-derived debris thickness maps can be used to calibrate and correct satellite-derived estimates, bridging the gap between spatial and temporal scales. Despite the relatively large RMSE in debris thickness estimates, this study is the first to discuss the limits and opportunities of UAV-derived LST to study the evolution of debris-covered glaciers. While UAV-derived LST can provide insights into glacial landscape changes over short time scales and relatively small spatial extent, detecting and monitoring longer-term changes at mountain range scale require long LST records and high spatial resolution to account for the steep altitudinal temperature gradients. In Chapter 3, I access patterns and trends in Landsat-derived LST data across the Swiss Alps using a harmonic model including a linear trend component. Comparison with LST time series from 119 weather stations revealed good accuracy of Landsat LST and LST trends. However, LST trends are biased due to orbital changes that cause variations in acquisition times, affecting the temporal coherence of LST measurements. Analysis of high temporal resolution LST from alpine weather stations shows that the linear change in Landsat acquisition time can explain a trend of 0.045 K y-1. However, the LST trend bias varies with topography, and I used modelled incoming shortwave radiation as a proxy to estimate the spatial variability of the LST trend bias. The corrected LST trends suggest that the highest LST warming rates are found in regions where mean annual land surface temperature is between -5 and 0°C and snow cover loss and permafrost thaw are expected to be large. In Chapter 4, I used several land cover datasets and created binary masks to compare the distributions of LST trends and their elevational differences for selected land cover and land cover change categories across the European Alps. Despite significant uncertainties in some of the binary masks, mean LST trends significantly vary with land cover and land cover changes, with a spatially averaged mean LST trend of 0.09 Kyr-1. The analysis further shows that warming rates of regions with significant snow cover loss increase with elevation, while other land cover types do not show such patterns. The studies in this thesis are the first to access LST and LST trends at unprecedented high spatial resolution, contributing to a better understanding of the climate sensitivity of glacial landscape dynamics and identifying regions prone to warming-related natural hazards.
Weniger anzeigenThe porcine reproductive and respiratory syndrome virus (PRRSV), an Arterivirus stands as one of the most impactful infectious pathogens, causing substantial economic losses in the swine industry. The minor glycoprotein Gp3 possesses an unusual hairpin-like membrane topology. The N- and C-terminus are exposed to the outside of the virus particle and anchoring to the membrane is achieved by an amphiphilic helix. The objectives of this study were to investigate the influence of the amphiphilic helix and the C-terminus of GP3 on viral replication in cell culture and to investigate whether the amphiphilic helix can be replaced by another amphiphilic helix with the same properties. I demonstrate that deletion of the C-terminal region leads to a slowdown in virus growth compared to the wild-type virus. Notably, the virus regains the C-terminus of GP3 after serial passage in cell culture. Moreover, substituting amino acids in the hydrophilic face of the helix with alanine results in the failure to rescue the virus, while the exchange of hydrophilic amino acids with more hydrophobic ones either causes virus rescue failure or strong reduction in virus titer. Additionally, swapping the position of two pairs of amino acid within the amphiphilic helix, which maintains its hydrophobicity and amphiphilic character, prevents rescue of infectious virus particles. Intriguingly, despite these alterations, the amphiphilic helix with substituted amino acids retains its binding capacity to membranes. This underscores that the amphiphilic helix cannot be replaced by another amphiphilic helix with similar biophysical properties without affecting the virus's behavior. Finally, five inhibitors were tested on PRRSV-1 and PRRSV-2 replication and it was shown that Remdesivir, GS-441524, EIDD-2801 and Ribavirin effectively inhibit virus replication whereas GC376 have no effect.
Weniger anzeigenThe determination of the transfer of undesirable substances and contaminants from oral exposure of farm animals into food of animal origin is essential to human risk assessment and management. The aim of this thesis was to develop physiologically-based toxicokinetic (PBTK) models that can be used to predict the concentration of specific contaminants in food of animal origin, based on the concentration in feed. Three groups of toxins were considered in the modelling approaches: polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), for short “dioxins”; polychlorinated biphenyls (PCBs); and quinolizidine alkaloids (QAs). As the first two groups, dioxins and PCBs, are quite similar from a kinetic point of view, they have been evaluated together and separately from the QAs. To gain a better understanding of the current state of research on the transfer of dioxins and PCBs to cow’s milk, a review of the literature was first compiled and published in two parts. This showed that although many modelling approaches have been developed, sufficiently complex models are often based on limited data sets. Therefore, there is still an urgent need for PBTK models that have been validated with sufficient data to accurately predict the transfer of dioxins and PCBs into milk and tissue. Within the framework of this thesis, two well parameterised PBTK models were successfully developed on a broad basis of experimental measurements. The first published model is based on data derived from a PCB contamination incident and describes the distribution of three non-dioxin-like (ndl) PCBs in various tissues and milk of an adult cow during two lactations and one dry period as well as in their calves. This also includes the transfer of the investigated ndl-PCBs from the adult cow to her calf via placenta and milk. Of particular note is the ability of the model to distinguish between placental transfer and milk transfer through suckling with 10-14 % of the amount of congeners in calves at slaughter was due to placental transfer. Several parameters were derived for risk assessment quantifying theses transfer and distribution processes. The second published model uses data from a feeding study in which dairy cows were fed a mixture of numerous dioxins and PCBs at different time intervals during their negative energy balance (NEB) and positive energy balance (PEB) phases to assess the effects of different metabolic states on the transfer of contaminants into milk. This was done with a three-compartment model that was parameterised separately for the NEB and PEB phases and reliably predicts the concentration-time (ct) profile of the investigated contaminants in milk and blood. It is particularly worth mentioning that some of the parameters derived here were reported for the first time. Comparison of the parameters obtained in the different energy balance phases revealed that the transfer rates of the investigated contaminants are significant higher in the PEB phase than in the NEB phase. Significant differences were also found for other parameters such as β half-lives, but to a much lesser extent. In the second part of the thesis, the knowledge gained from modelling approaches with dioxins and PCBs in cows was used to develop a model describing for the first time the transfer of three ndl-PCBs from feed into tissues of fattening pigs. The PBTK model was based on a feeding study in which fattening pigs were fed with ndl-PCBs contaminated feed at different stages of their fattening period. The model consists of a liver and a fat compartment, which allows to describe the concentration of ndl-PCBs in the most relevant tissues for the consumer, i.e., muscle (based on its fat content) and liver. In addition, various transfer parameters were derived, which allows the quantification of the extent of transfer of these contaminants to these tissues under realistically changing feeding conditions and animal growth. The lowest transfer rate was obtained for PCB-28 with 9.57 % and the highest transfer rate was obtained for PCB-153 with 77.2 %. In the final part of this thesis, QAs in dairy cows were investigated, which are kinetically completely different in their behaviour in comparison to dioxins and PCBs. QAs are potentially toxic plant secondary metabolites from lupins, a high-protein crop. Based on a feeding study in which dairy cows were fed subsequently with different amounts of QA-containing lupins, a PBTK model was developed to investigate the transfer of QAs into milk and its dose-dependency. As QAs are eliminated much faster from the body of the cows than dioxins and PCBs, aspects such as milking time and feeding time had to be taken into account. Since the ct-profile of QAs in milk during the depuration showed a biphasic behaviour, a three-compartment model was developed that induces a biphasic depuration phase in milk. This made it possible to describe the measured data quite well despite the high variability of the data points. The size of the experiment and the limited difference between the doses applies allowed no conclusion regarding a possible dose-dependent transfer. Several risk assessment parameters were derived, including transfer rates ranging from 1.05 % for angustifoline to 2.92 % for isolupanine and α-half-lives ranging from 0.26 d lupanine to 0.28 d hydroxylupanine. However, the very low concentrations covered by the β-half-lives are not expected to be relevant for risk assessment. In summary, in the scope of this work, several PBTK models were successfully developed that describe and quantify the transfer of various contaminants to dairy cows, calves and fattening pigs. To make these models accessible to risk assessors, they will be implemented in the web tool BfR ConTrans.
Weniger anzeigenThis work investigates the use of ion mobility spectrometry and gas-phase infrared spectroscopy in combination with mass spectrometry for the structural analysis of isomeric sulfated glycans. Both methods have been successfully applied for the analysis of glycans before. Ion mobility spectrometry offers a structural dimension, missing in classical mass spectrometry for the differentiation of isomeric structures, while infrared spectroscopy can provide detailed structural information of even gas-phase conformations. These methods allowed for the investigation of the interaction of glycosaminoglycan with magnetic resonance imaging probes, revealing an intricate binding motive and a surprising dissociation behaviour. They allowed for the separation and quantification of twelve partially isomeric sulfated disaccharides, which previously were analyzed by tedious and time-consuming liquid chromatography methods. And finally, they revealed two unknown sulfated glycan-specific gas-phase rearrangement processes, which further consolidate the unique challenges faced in the structural analysis of sulfated glycans.
Weniger anzeigenZiel der Dissertation ist es, die Sonetti del Burchiello aus hermeneutischer Sicht zu analysieren. Bei den SdB handelt es sich um ein poetisches Corpus, das um die Produktion von Domenico di Giovanni detto il Burchiello (Florenz 1409 - Rom 1449) entstanden ist, dennoch hat es keine auktoriale Intention. Die fragmentierte und kontaminierte Manuskripttradition der Sonette hat in der komplexen vulgate der zweiten Hälfte des 15. Jahrhunderts eine stark gemischte Kanonisierung begründet und in dieser Form hat sie sich weiterverbreitetet. Erst im Jahr 2000, dank der innovativen Perspektiven und der systematischen Methodologie von M. Zaccarello, wurde dieses komplexe Corpus in einer ersten kritischen Edition konkretisiert. Diese Ausgabe, die auf den kulturellen Kontext der Verlagspraxis des Quattrocento fiorentino bezogen ist, hat eine wichtige Revitalisierung der burchiellesken Kritik in den letzten Jahren ermöglicht. Das Ziel meiner Arbeit ist es, verschiedene disziplinäre Perspektiven (Textkritik, Literaturtheorie, Textanalyse und Komparatistik) durch eine interdisziplinäre Reflexion über das Denken von Michail M. Bachtin (Oriol 1895-Moskau 1975) zusammenzuführen, insbesondere auf Basis des Prinzips der "Dialogizität" in den verschiedenen Formulierungen, die Bachtin und seine ‚Forschergruppe‘ entwickelt haben. Nach einer Einführung in den aktuellen Stand der Forschung zu Burchiellos corpus stelle ich die Analyse des Phänomens der tenzone in Bezug zu den SdB dar, um die poetologische Formulierung des Prinzips der "Dialogizität" voranzutreiben, die dieser Arbeit zugrunde liegt. In diesem Sinne betrachte ich die Merkmale und Probleme der Bachtin-Rezeption in der zweiten Hälfte des zwanzigsten Jahrhunderts. Anschließend wird ein kritischer Überblick über die wichtigsten Beiträge gegeben, die sich bisher mit dem "Gleichklang" des burchiellesken und des bachtinianischen Diskurses befasst haben: Wir beginnen mit einer Kontextualisierung der eher "traditionellen" Verbindung, die zwischen dem Corpus der komischen Gedichte Burchiellos und Bachtins berühmter und umstrittener Monografie Rabelais und seine Welt. Volkskultur als Gegenkultur geäußert wurden, vor allem analysiere ich die wichtigsten Konzepte des "Karnevalesken" und des "grotesken Realismus", deren Verwendung ich aus einem anderen hermeneutischen Blickwinkel vorschlage. Andere Beiträge Bachtins, die auf seine intellektuellen Anfänge in den 1920er und 1930er Jahren zurückgehen (aber in einem langen Prozess theoretischer Reflexion entwickelt wurden), spielen in diesem Werk eine ebenso wichtige Rolle: Erstens Bachtins Konzept der "Textualität", das eine neue Perspektive bietet, um die methodologische Komplexität der burchiellesken Tradition zu betrachten; zweitens das Konzept der "Architektonik" des künstlerischen Werks (das im Vergleich mit anderen Beiträgen zur Autorschaft thematisiert wird), das es ermöglicht, verschiedene Autorfunktionen im burchiellesken Corpus zu problematisieren; und schließlich wird Bachtins Reflexion über die Beziehung zwischen "diskursiven Gattungen" und "literarischen Gattungen" die Möglichkeit bieten, eine textuell-komparatistische Analyse durchzuführen, wobei die Besonderheit des Sonetto caudato eine analytische Grundlage für die Beobachtung der Kodifizierung des burchiellesken Sonetts im 15. Jahrhundert darstellt. Diese Analyse hebt auch die Konvergenz des SdB mit anderen poetischen Gattungen – sowohl frühere (im französischsprachigen Raum), als auch spätere (im spanischsprachigen Raum) - hervor. Meine Arbeit hat den Fokus auf der poetischen Gattung als "Gravitationszentrum" und beobachtet den diskursiven Fluss der Sonette aus einer Perspektive, die sich nicht mehr auf einen traditionellen auktorialen und "binären" Vergleich konzentriert, sondern vielmehr auf die Berücksichtigung anderer zentraler Faktoren, die die poetische Praxis und die kulturellen Koordinaten des Textes zwischen dem 14. und 16. Jahrhunderts verkörpern. Die Studie möchte auch neue methodologische Perspektiven für die Analyse anderer poetischer Phänomene (jenseits des Quattrocento fiorentino) anbieten, insbesondere für die burleske Lyrik des Siglo de Oro.
Weniger anzeigenDie Arbeit mit dem Titel „Von Kontext zu Kontext. Verfahren der Aneignung gefundener Fotografien bei Mike Mandel, Larry Sultan und Peter Piller“ geht der Frage nach, wie sich Künstler*innen von ihnen gefundene, fremde und nicht für einen genuin künstlerischen Zweck hergestellte Fotografien für ihre Arbeiten aneignen, welche Präsentationsformen sie wählen und welche Bedeutung die Art der Präsentation für eine Rezeption und Konstituierung der Fotografien als Kunst hat. Die Studie gliedert sich in drei Hauptteile. Im ersten Teil wird anhand einer kunsthistorischen Verortung untersucht, seit wann Künstler*innen fremde Fotografien in eigene Werke einbanden, auf welchen Wegen Fotografien des Alltags in die Kunstwelt gelangten und wie die Aneignung fremder Fotografien juristisch zu bewerten ist. Die nächsten beiden Kapitel stellen exemplarische Werkanalysen dar, in denen produktions- und rezeptionsästhetische Ansätze miteinander verbunden werden. Untersucht wird zum einen die Arbeit Evidence von Mike Mandel und Larry Sultan, welche 1977 zuerst als selbstverlegtes Buch und später in zahlreichen Ausstellungen präsentiert wurde. Zum anderen wird Peter Pillers Ende der 1990er begonnener Werkkomplex Archiv Peter Piller analysiert. Hier wird teilweise zum ersten Mal sowohl das künstlerische Vorgehen und die Formgebung als auch die Wirkung und kunsthistorische Bedeutung der ausgewählten Arbeiten anhand ihrer Ausstellungs-, Editions- und Rezeptionsgeschichte untersucht, welche im Fall von Evidence über 40 Jahre, im Fall des Archiv Peter Piller über 20 Jahre umfasst. Die Analysen basieren im Wesentlichen auf einem kunsthistorisch vergleichenden Ansatz. Sie widmen sich der Materialität der künstlerischen Arbeiten und untersuchen deren räumliche und mediale Präsentationskontexte – die Hängung von Fotografien an Ausstellungswänden und ihre Präsentation in Büchern – sowie die Gleichzeitigkeit dieser Präsentationsformen und ihren Wechsel. Es wird gezeigt, dass es nicht nur Künstler*innen, sondern auch Kurator*innen und Verleger*innen waren, die dazu beitrugen, dass sich bereits in der ersten Hälfte des 20. Jahrhunderts eine eigenständige Tradition im künstlerischen, kuratorischen und editorischen Umgang mit gefundenen Fotografien entwickelte. Die Verfahrens- und Kontextanalysen verdeutlichen, dass die ausgewählten Künstler mit ihrem Vorgehen die Grenzen zwischen editorischen, kuratorischen und künstlerischen Aneignungsverfahren aufweichen und bewusst darauf abzielen, auch die Klassifizierbarkeit der von ihnen angeeigneten Fotografien zu erschweren. Zudem belegt die Analyse, dass die ausgewählten Werke nicht allein durch die simple Entnahme von Fotografien aus einem Kontext und deren Eingabe in einen anderen Kontext entstehen, sondern vielmehr aus einem komplexen und mehrschrittigen Prozess hervorgehen, der unter anderem eine materielle Bearbeitung der gefundenen Fotografien beinhaltet.
Weniger anzeigenThe human teeth characteristics in this study carried out two different themes, namely human demography and behavior from the late Holocene to the Current Era. The human teeth were unearthed in the seven archaeological sites in the lowlands of Papua Indonesia was analyses to answer the questions about human ancestry, kinship group relationship, and their diet behavior in the past. The molecular analysis was performed with two different methods: ancient DNA and stable isotope analysis, to answer the study questions. In addition, the morphological metric dental study and wear pathology identification was conducted to provide another perspective on human ancestry and diet behavior. The results present evidence of human genetic impact from Asia in the lowlands of Papua, using two different pathways, from Taiwan through the Philippines to the coastland part of Papua and from Peninsular Southeast Asia by the use of Sundaland as a route to eastern Indonesia until Oceania. At the same time, intermarriage happened between population lineage: Papuan and Asian, derived from the mtDNA and Y-haplogroups results in this study. The diet behavior identification resulted from the evidence of the humans living in the late Holocene time, their diet subsistence by gathering the marine sources and foraging the terrestrial foods. The impact of these diet activities is displayed by the morphological analysis of their teeth, presenting a high wear rate due to food consumption. Because of the tropical climate, high temperatures, high humidity, and other preservation factors, not all samples processed in this study could go through all intended molecular analyses. Hence, it is hoped that future scientific discoveries will reveal further details or harden the theories derived from this study. This dissertation is organized as follows: Chapter 1 gives an introduction about Modern Human history, including the theory about human dispersal originating from Africa into all parts of the world, including to the area of Papua or New Guinea, which was developed in several decades. Chapter 2 provides a literature review with a broad overview of human history based on linguistic studies, archaeology, physical anthropology, and genetic studies done in New Guinea island. The brief review of human history from these study sources helps explore human migrations, contact, diet behavior, and other human cultural practice in this area. Thus, these studies were performed to understand human history and behavior in the lowland area of Papua-Indonesia. Chapter 3 presents the methods and materials employed in this dissertation. The metric teeth traits are described in this section, and the statistical methods used to divine the frequency of trait variation. The ancient DNA analysis contains several steps, including sampling, DNA extraction, library preparation, and genomic data processing, to compare the DNA of the individuals in this study for ancestry identification. Finally, the stable isotope study is performed to determine the past human diet intake and identify teeth wear and pathology impacted by human diet behavior and diseases experienced by the lowland Papuan. Chapter 4 provides the statistical analyses of metric dental traits, aDNA result, the stable isotopes of nitrogen, carbon, and oxygen, and the results from wear and teeth pathology analysis. Chapter 5 presents the discussion of the statistical metric analysis and aDNA results, compares them to the hypothesis, and describes the resulting interpretation and implications. The discussion of stable isotope results and their correlations to the ecofact distributions provide human diet patterns and movement behavior in the past. The discussion about wear, including macro and microwear and teeth pathology, is discussed in this chapter and connected with the stable isotope results. Chapter 6 provides a conclusion and the potential future directions of research to understand the history and behavior of the lowland inhabitants of Papua in terms of metric traits, ancient DNA results, diet behavior, teeth wear, and teeth pathology. The literature, appendices, and glossary are provided at the end of this dissertation.
Weniger anzeigenIn recent years, scientific research has faced significant challenges, including the rise of "fake news" on social media, which has complicated the public's perception of scientific truth. This is juxtaposed with the scientific principle of falsification, where hypotheses are not proven but rather refuted. Additionally, the reproducibility crisis—where many scientific findings cannot be consistently replicated—has become a pressing issue, highlighted in journals like *The American Statistician*. The discourse around p-values, with some suggesting their abandonment, underscores the call for more robust statistical analyses to ensure trustworthy scientific conclusions. This work explores methods to validate and enhance the robustness of statistical techniques for their effective application in real-world data scenarios. In clinical research, the objective of translating findings from the laboratory to patient care is crucial. This is structured by the 4T model: starting from basic research (T1), moving to evidence-based guidelines (T2), then transforming into clinical practices (T3), and finally improving community health outcomes (T4). Throughout these stages, biometry and statistical bioinformatics play a vital by developing robust methods that can validate clinical research findings. For example, the median offers a robust measure of central tendency less affected by outliers compared to the mean, thus providing more reliable results. The era of "big data" has led to unprecedented data volumes, posing new challenges in data management and analysis, and giving rise to the field of data science. In biometry, big data challenges were first encountered with genetic microarray technology, presenting the "high-dimensional data problem" where the number of parameters exceeds the sample size. This is illustrated in genome-wide association studies (GWAS), where genetic data consisting of hundreds of thousands of variants are analyzed to predict and classify diseases such as rheumatoid arthritis, demonstrating the necessity for innovative data processing and analytical methods to manage such complex datasets effectively.
Weniger anzeigenDer vorliegende Band bietet eine umfassende Untersuchung der rituellen Niederlegungen der neolithischen Trichterbecherkultur (4100–2800 v. Chr.). Trotz einer langen Geschichte der Erforschung seit der zweiten Hälfte des 19. Jahrhunderts fehlte bisher eine aktuelle Gesamtzusammenfassung und Auswertung dieses Phänomens. Die Studie schließt diese Lücke und legt dabei einen besonderen Fokus auf Deponierungen mit Steingeräten, insbesondere Beilklingen aus Feuerstein, die das zentrale Thema der Deponierungen darstellen. Rund 3500 Artefakte aus 63 verschiedenen Museen und Sammlungen in fünf Ländern hat der Autor für diese Arbeit analysiert und fotografiert. Durch quellenkritische Analysen und Methoden zur Identifizierung von Deponierungen konnten wichtige Erkenntnisse gewonnen, eine neue Typologie für Beilklingen entwickelt sowie Schätzungen zu ihrer Herstellungszeit vorgenommen werden. Untersucht werden zudem die Zusammensetzung der Depots, ihre geografische Verteilung, ihre Lagebeziehung zu trichterbecherzeitlichen Siedlungen und Gräbern sowie die Inszenierung der niedergelegten Objekte. Schließlich diskutiert das Buch die Bedeutung der Deponierungen innerhalb der trichterbecherzeitlichen Gesellschaften und sieht die mit den Niederlegungen einhergehenden rituellen Handlungen als Ausdruck sozialer Zusammengehörigkeit im Kontext eines Glaubenssystems, das möglicherweise einen zentralen Aspekt des trichterbecherzeitlichen Lebens darstellte und sich schließlich auch in monumentalen Bauwerken manifestierte.
Weniger anzeigenAntibacterial activity of marine sea cucumber and oyster against Staphylococcus aureus and Vibrio
Oceans and seas are home to a large proportion of all life on Earth, with 71% of the Earth's surface being ocean water, while only 2.5% is drinkable freshwater. Oceanic plankton, algae, and certain bacteria contribute significantly to this large proportion. Marine habitats are divided into coastal and open ocean habitats, with coastal habitats occupying only seven per cent of the ocean surface. The organisms studied range from microscopic phytoplankton and zooplankton to whales in the open ocean. Invertebrates are an important part of marine life, providing food, medicine, and raw materials. Advancement of invertebrate-derived compounds is a therapeutic prospect for biomedical discovery. Marine natural product drug discovery efforts have yielded nine approved drugs and 12 currently under clinical trial, largely from collections of marine invertebrates from shallow-water tropical ecosystems. The global fish production industry has a significant impact on national economies, providing 17% of the animal protein consumed by the global population, and providing health benefits. Aquaculture is a significant contributor to the global food fishery industry. Sea cucumber is a marine invertebrates widely consumed in East Asia due to its multiple biological and pharmacological properties, including anticancer, anti-angiogenic, anticoagulant, anti-inflammatory, anti-hypertension, antimicrobial, antithrombotic, antioxidant, and antitumor properties. The Persian Gulf is a biodiverse ecosystem with Holothuria leucospilota being the most commonly harvested sea cucumber. However, only 20 articles have investigated the Persian Gulf's Holothurian species. Previous investigations have shown that high concentrations of Holothurian compounds have a weak antibacterial effect. Sea cucumber protein hydrolysates are a healthy and reliable alternative to artificial food preservatives. Staphylococcus aureus is one of the most prevalent pathogens responsible for food poisoning, and the emergence of antimicrobial resistance in S. aureus is a public health concern. In chapter II, I studied by using extraction of bioactive compounds from sea cucumber Holothuria leucospilota revealed antibacterial effects on MRSA and enterotoxin-producing Staphylococcus aureus strains (SEASA, SEBSA) were determined. Three methods were used to determine antimicrobial activity: disc diffusion experiments, the minimum bactericidal concentration (MBC), and the minimum inhibitory concentration (MIC). The results indicate that methanol and chloroform extracts inhibit the growth of all tested isolates at MIC concentrations as high as 100 mg/ml. In concentrations of approximately 100 mg/ml, the chloroform extract exhibited bactericidal activity against SEBSA. In concentrations below 100 mg/ml, the extract is also bactericidal against MRSA and SEBSA. Methanol extract demonstrated the greatest antibacterial activity. Therefore, sea cucumber extract is a promising candidate for the discovery of new antimicrobials; however, extensive research is required to isolate and identify the active components of Holothuria leucospilota from the Persian Gulf. I found Sea cucumber extracts can considered to possess antimicrobial properties. My results support the idea that the sea cucumber extracts are considered a healthy and dependable alternative to artificial food preservatives is illustrative of their antimicrobial activity. Aquaculture contributes to global fish production and health benefits.Vibriosis is a potentially fatal infection caused by Vibrio species, which are abundant in marine and estuarine ecosystems and can cause human cutaneous infections and gastrointestinal disorders. Vibrio spp is increasing due to climate change, and Pacific Oyster Crassostrea gigas is an appropriate model for the study of Vibrio and host interactions in disease dynamics. Investigation of interactions between oysters and vibrio.spp is essential to prevent bacterial diseases and mortality in aquaculture. Fluorescence in situ Hybridization FISH was used to visualize diversity of v.Kanaloae in different tissues. In chapter III, investigated on the C. gigas oysters from Sylt Island were exposed108 V. kanaloae strains T02 and S12 in the summer of 2020 .Consequently, different oyster organs were analyzed by the culture-independent molecular technique, Fluorescence in situ Hybridization (FISH) to rapidly visualize the diversity of v.Kanaloae in different tissues of the oyster on the 3rd day post-infection due to the fact that cellular immune parameters peaked on day 3 demonstrating primarily a response to the immune challenge. Consequently, our findings offer a novel perspective on invasion efficacy. During an investigation into its in vivo distribution, the digestive organs, gills, and muscles were found to contain Vibrio kanaloae. Aquaculture production including fish, oysters, molluscs exceeded 177.8 million metric tonnes in 2019. Vibrio splendidus is affecting global production of C. gigas oysters. Oysters have an integrated, highly complex innate immune system to identify and eliminate invaders, with both innate and adaptive immunity. The genome of the Pacific oyster C. Gigas has revealed massive expansion and functional divergence of innate immune genes. Immune priming in enhances the immune response upon subsequent exposure to V. splendidus. Immune priming involves two mechanistic models: a biphasic response followed by an extinction phase, and a unique response initiated after priming . Immunostimulants can increase the resistance of aquatic organisms to infectious diseases by enhancing their defense mechanisms. In chapter IV, I investigated on Pacific oysters (Crassostrea gigas) primed with 104 Vibrio splendidus exhibited stronger immune responses when challenged with 107 V. splendidus. In addition, we inoculated the oysters against Vibrio by exposing them to sympatric and allopatric V. splendidus strains in order to evaluate their resistance in vivo and determine if this colonization increases virulence and survival. Oysters that had been cross-protected against the sympatric strain of V. splendidus survived a secondary challenge better. In addition, we examined the priming of the bacterium Vibrio by exposure to colonized oysters in order to determine their resistance to haemolymph in vivo experiment. We analyzed the immunological responses of oysters to determine if colonization leads to an increase in mortality. In the oyster model, the selected isolates demonstrated increased survival in both the primary and secondary challenges, as well as in vitro protection against V. splendidus. Selective populations of oysters resistant to V. splendidus exhibited an increase in in vivo survival, an inhibitory effect on V. splendidus in vitro during a secondary challenge, and cross-protection against V. splendidus in vitro examination. In this thesis, I investigated hypotheses explaining the Sea Cucumber H. leucospilota has antibacterial effects against S. aureus strains MRSA, SEASA, and SEBSA, but further research is needed. FISH is a valuable and rapid technique for detecting and quantifying V. kanaloae's living forms. Using the developed method, viable V. kanaloae in oysters can be identified. The Vib-16S-1 instrument can be used to determine the pathogenic species of Vibrio that is most prevalent. Due to the direct visualization of bacteria, the detection time can be significantly reduced compared to culture-based methods. Immunopriming was shown to stimulate oyster humoral immune responses against both sympatric and allopatric strains of V.splendidus in order to improve specific memory and adaptive immunity in oysters. which could be used for oral vaccine programs to prevent aquaculture disease outbreaks. Further investigation is required to determine the prospective mechanism responsible for the observed changes. Objective In my dissertation, I conducted an in-depth investigation into microbial interactions in aquatic organisms and their implications for seafood safety, disease dynamics, and biocontrol strategies. The study delves into the intricate realm of microbial interactions, with a specific focus on the sea cucumber Holothuria leucospilota and the Pacific oyster Magalana gigas. Through a series of interconnected chapters, the research endeavors to establish a thorough understanding of these interactions, offering valuable insights into seafood safety, the dynamics of diseases, and the potential development of biocontrol strategies. Sea cucumber Holothuria leucospilota Extracts This chapter explores the antimicrobial potential of extracts obtained from Holothuria leucospilota, emphasizing their effectiveness against Staphylococcus aureus, including methicillin-resistant strains and enterotoxin producing Staphylococcus aureus strains (SEASA, SEBSA. The primary objective was to identify bioactive compounds within the sea cucumber extracts possessing antibacterial properties. By doing so, this chapter lays the groundwork for investigating natural antimicrobials in marine organisms, positioning the sea cucumber as a promising source for the discovery of novel antimicrobial agents and a particular emphasis on their suitability as substitutes for synthetic food preservatives. Vibrio Dynamics in Oysters Chapter III examined the relationship between Pacific oysters (Crassostrea gigas) and Vibrio species, particularly Vibrio kanaloae, in the context of disease dynamics. The technique of molecular fluorescent in situ hybridization (FISH) was used to quickly determine the range of bacteria present in Crassostrea gigas. This allowed for important observations on the metabolic activity and distribution of Vibrio strains throughout the tissues of the oysters. This chapter establishes the fundamental concepts necessary to comprehend the dynamics between hosts and pathogens, thereby creating a foundation for investigating the influence of microbial interactions on the health of oysters. Immune Priming in Oysters In this chapter, our main goal is to investigate the specificity of immune priming responses in Pacific oysters (Magalana gigas) as a potential strategy for biocontrol against pathogenic Vibrio strains, particularly Vibrio splendidus, with a focus on mitigating high summer mortalities in aquaculture. We explore the nuances of immune priming by exposing oysters to sympatric and allopatric V. splendidus strains, assessing the inhibitory effects of haemolymph plasma, and examining cross-protection against lethal Vibrio challenges. The research sheds light on the correlation between strain origin and the effectiveness of immune priming, emphasizing the potential of matching local strains for optimal protection. Ultimately, the findings aim to contribute to the development of targeted biocontrol measures to safeguard oyster production and address economic implications in the food industry. Conclusion Expanding on the knowledge acquired from Chapters II, III, and Chapter IV, this section explores the immunological priming responses demonstrated by Pacific oysters, namely Magalana gigas, when exposed to pathogenic Vibrio strains. The objective is to examine the degree of immunological priming specificity by studying closely similar strains of Vibrio splendidus. This chapter attempts to investigate the possibility of immune priming as a biocontrol technique against high summer mortalities in oyster populations by analyzing the inhibitory effects of oyster haemolymph on Vibrio growth.Collectively, these chapters establish a coherent story that covers the discovery of natural antimicrobials in marine organisms (Chapter II), the comprehension of disease patterns in oysters (Chapter III), and the investigation of immune priming as a possible approach to control Vibrio-induced mortality in aquaculture (Chapter IV). This dissertation enhances our comprehension of microbial interactions in aquatic habitats, which has significant implications for ensuring seafood safety and implementing sustainable management practices in aquaculture systems.
Weniger anzeigenDie Disziplin „Vielseitigkeit“ steht aufgrund von Stürzen während anspruchsvoller Geländeprüfungen zunehmend in der öffentlichen Kritik. Die Geländeprüfung auf internationalem 2-Sterne- bis 4-Sterne-Niveau entspricht einer submaximalen Belastung. Die Erfassung blutbasierter Ermüdungs- und Erholungsmarker liefert quantifizierbare und objektive Ergebnisse. Eine Individualisierung der Referenzbereiche für ausgewählte Parameter kann die Leistungsdiagnostik verbessern. Ein Parameter ist dann für eine Individualisierung geeignet, wenn er belastungsabhängig ansteigt und mit einem belastungsrelevanten physiologischen Vorgang zusammenhängt. Die Erstellung gruppenbasierter Referenzbereiche für ausgewählte Zeitpunkte vor und nach Belastung ist der erste Schritt der Individualisierung, da die Blutwerte bei Vielseitigkeitspferden nach Geländeritten regelmäßig von den Referenzbereichen für gesunde Pferde in Ruhe abweichen. Während der Geländeritte kommt es zu einer Kontraktion der Milz und zu einer Plasmavolumenverschiebung von intravasal nach extravasal. Eine Adjustierung der Blutwerte mithilfe der Albuminkonzentration verbessert die Beurteilung der Belastungsabhängigkeit der untersuchten Blutparameter. Die größten prozentualen Abweichungen 30 Minuten nach Belastungsende aller belastungsabhängigen Parameter weisen die folgenden zehn Parameter in absteigender Reihenfolge auf: Laktat, GLDH, Cortisol, cTnI, CK, T3, Kreatinin, HCT, Triglyceride, Anorganisches Phosphat. Die Beurteilung der Ermüdung ist im verwendeten Versuchsaufbau nicht allein anhand von Blutwerten möglich. Eine weitere Einschränkung der Studie besteht darin, dass die statistische Analyse nicht über die Ebene von Mittelwerten hinausgeht und eine Identifikation auffälliger Pferde deshalb nicht möglich ist. Um zu beurteilen, ob der gemessene cTnI-Anstieg ein Hinweis auf pathologische kardiale Ermüdung bei Vielseitigkeitspferden ist, sollten weitere Untersuchungen durchgeführt werden. Eine Analyse der blutbasierten leistungsdiagnostischen Marker sollte im Saisonlängsschnitt erfolgen und zusätzliche nicht-blutbasierte Messwerte sollten in die Beurteilung von Ermüdung und Erholung einbezogen werden.
Weniger anzeigenGiven a (usually small) graph H and an n-vertex graph G the H-bootstrap process on G is defined to be the sequence of graphs which starts with G and in which each graph is obtained from the previous one by adding every edge that completes a copy of H. This process eventually stabilises. We investigate the maximum running time of the process, which is the largest number of steps an H-bootstrap process on an n-vertex graph can take before it has stabilised, for several choices of H and initiate the study of which graph parameters determine the asymptotic growth of that number as a function of n. The first range of running times we consider is characterised by the question "For which H is the largest number of steps asymptotically sublinear?". Here we will see graphs such as trees and cycles, and we will provide sufficient conditions which guarantee that H does not have sublinear maximum running time. On the other hand we examine those H for which the maximum running time is asymptotically much larger than n. Within the superlinear range we will encounter graphs of high connectivity or high density, but also sparse graphs such as when H is distributed as the Erdős-Rényi random graph for certain edge probabilities. We put particular emphasis on graphs with quadratic maximum running time. To provide quadratic bounds we will generalise a construction introduced by Balogh, Kronenberg, Pokrovskiy, and Szabó to study the case when H is a complete graph.
Extremal constructions from additive combinatorics provide some of the best-known lower bounds on running times in graph bootstrap percolation. In the second part of the thesis we focus on an extremal additive problem. We study sets of natural numbers with the property that for some h ≥ 2, the distance between any two distinct sums of h elements is at least a fixed power of the largest summand. By elaborating on a construction of Cilleruelo we give an infinite set that satisfies the condition above and whose counting function provides an improvement over the greedy construction.
Finally, we consider the problem of splitting matchings. Given a k-regular graph whose edge set is the union of k perfect matchings, we want to find a matching M that intersects each of the original matchings in a given number of edges. We are particularly interested in the situation in which a suitable M exists no matter what the initial matchings are. This question was introduced by Arman, Rödl, and Sales. Two special cases are fair splits and perfect splits. In the former case one takes the same number of edges from each of the original matchings, while in the latter M is itself perfect. We give necessary conditions on the existence of perfect splits as well as fair splits, and provide sufficient conditions for the case k=3.
Weniger anzeigenFlugunfähige Vögel sind in zoologischen Einrichtungen keine Seltenheit. In früheren Jahren war das Flugunfähigmachen von Vögeln die gängige Praxis, um sie daran zu hindern, ihrem Gehege zu entweichen.
Mit der Änderung des Deutschen Tierschutzgesetzes im Jahre 1998 wurde jedoch das irreversible Flugunfähigmachen durch Paragraph 6 des Deutschen Tierschutzgesetzes verboten. Nichtsdestotrotz gibt es auch die Ansicht, dass auch das reversible Flugunfähigmachen mittels Federschneiden unter diesen Paragrafen fallen würde.
So kommt es immer wieder zu kontroversen Diskussionen, ob der Vogel aufgrund seiner Flugunfähigkeit leidet, oder dies durch andere Verhaltensweisen kompensiert werden könnte. Jeglichen Argumenten fehlt aber die wissenschaftliche Grundlage, da der Zusammenhang zwischen dem Flugunfähigmachen eines Vogels und seinem Wohlbefinden bisher nicht wissenschaftlich untersucht wurde.
Mit der Entwicklung der Kortikosteron Messung aus der Feder eröffnete sich nun die Möglichkeit, erste Zusammenhänge tierbasiert untersuchen zu können. Da das Wohlbefinden von zoologisch gehaltenen Tieren immer mehr im Fokus der öffentlichen Debatte steht, mit der Forderung einer tiergerechten Tierhaltung, wurde diese Studie entwickelt, um erste Daten zum Rosapelikan (Pelecanus onocrotalus) in Bezug auf sein Wohlbefinden und dem Flugunfähigmachen zu generieren.
Hierzu wurden in 21 deutschen, zoologischen Einrichtungen Daten gesammelt, welche auf der Kombination von Verhaltensbeobachtungen und der Messung von Feder Kortikosteron beruhten. Insgesamt wurden 215 Rosapelikane mithilfe eines erstellten Ethogramms beobachtet. Pro zoologische Einrichtung wurden die Tiere drei Tage lang für je zwei Mal zwei Stunden am Tag mittels Scan-Sampling-Methode beobachtet. Die Pelikane der Gruppen wurden je einem Flugstatus zugeteilt: flugfähig, reversibel flugunfähig oder irreversibel flugunfähig. Im selben Jahr der Verhaltensbeobachtung wurden dann von den Pelikanen Federproben genommen und das Feder Kortikosteron gemessen. Hierbei wurden 182 Pelikane beprobt. Die Daten wurden in einem linearen gemischten Regressionsmodell analysiert.
Es zeigte sich kein signifikanter Unterschied im Feder Kortikosteron zwischen den einzelnen Flugstatusgruppen, jedoch waren Tendenzen ersichtlich. Die reversibel flugunfähig gemachten Rosapelikane zeigten die höchsten Feder Kortikosteron Werte. Auch die Gruppengröße der gehaltenen Rosapelikane hatte einen Einfluss, der jedoch nicht signifikant war. Hier hatten die größten Gruppen mit über 10 Tieren die niedrigsten Feder Kortikosteron Werte. Andere Variablen wie das Geschlecht oder das Alter der Tiere hatten ebenfalls keinen signifikanten Einfluss auf die Feder Kortikosteron Werte. In Bezug auf die Verhaltensbeobachtungen und die Feder Kortikosteron Werte zeigte sich ein signifikanter Zusammenhang mit höheren Werten an Feder Kortikosteron und dem Verhaltensmuster flattern.
Es konnten somit Daten zu den Rosapelikanen in zoologischen Einrichtungen erhoben werden, die einen ersten Überblick über diese Art verschaffen.
Das Flugunfähigmachen scheint somit keinen signifikanten Einfluss auf das Wohlbefinden der Rosapelikane zu haben, obwohl Tendenzen ersichtlich waren. Das Verhaltensmuster flattern könnte ein Indikator für Stress sein, da hier höhere Feder Kortikosteron Werte festgestellt wurden.
Jedoch sind dies die ersten Ergebnisse der ersten Untersuchungen an Rosapelikanen in zoologischen Einrichtungen und diese sollten durch weitere Studien validiert werden.
Weniger anzeigenBackground: Ascariasis is one of the most common soil-transmitted helminth infections worldwide and a considerable problem in animal agriculture. The infection is spread via the fecal- oral route and occurs following ingestions of eggs containing infective third-stage larvae. These eggs hatch, releasing larvae which then invade the host intestine and embark on a tissue migration phase which takes them through the host’s liver and lungs before returning to the small intestine. This tissue migration leads to the immune responses, pathologies, and symptoms characteristic of ascariasis. In the jejunum, the worms mature and live amongst host microbes. Current efforts to control helminth infections have been somewhat successful but have not been able to eradicate these pathogens. Thus, novel insights into their lifestyle within the host are needed to unveil new therapeutic modalities. Much remains unknown concerning their interactions with microbes in the host intestine. Therefore, this thesis aimed to unravel interactions between Ascaris and microbes by characterizing antimicrobial activities of the worms as well as the first description of the Ascaris microbiome and its key determinants by completing the following aims:
1. To determine if Ascaris nematodes release antimicrobial compounds in their excreted and secreted products. 2. To characterize the antimicrobial activities of these products. 3. To characterize the Ascaris microbiome. 4. To identify the primary determinants of Ascaris microbiome composition.
Results: The excreted and secreted products of A. suum were found to contain a variety of proteins and peptides with known and predicted antimicrobial activity, including antimicrobial peptides from different families and C-type lectins. These products exhibited diverse antimicrobial activities, including bacterial growth inhibition, disruption of bacterial Biofilm formation, and agglutination. We further characterized one of the proteins secreted by Ascaris, a C-type lectin domain-containing protein we have named AsCTL-42. This lectin recapitulated the agglutination observed for Ascaris ES products and inhibited invasion of porcine intestinal epithelial cells by Salmonella Typhimurium. Finally, we characterized the microbiome of Ascaris nematodes isolated from infected pigs and determined that the nematode’s own intestinal microbiome is derived, but distinct from, the microbes present in the host jejunum. Composition of the Ascaris microbiome is driven primarily by the dominant bacteria present at the site of infection; however, certain genera are enriched in the Ascaris intestine relative to the host.
Conclusions: Our results demonstrate that Ascaris acquires microbes from those present at the site of infection in the host jejunum and that these microbes are present in differential abundances in the worm relative to its host, suggesting that the worm might preferentially take up some bacteria while excluding others. Our data characterize potential mechanisms by which the worm might modulate its microbiome as well as that of its host by demonstrating antimicrobial activities of its excreted and secreted products which contain various antimicrobial effector molecules. Our data provide a foundation for further work which can assess the impacts of interactions between Ascaris, microbes, and host cells on co-infecting pathogens while determining which microbes are beneficial or harmful for the worm.
Weniger anzeigenDiese Untersuchung hat zum Ziel, die Beziehung zwischen Arbeiten zeitgenössischer performativer Künste und dem Anthropozän, dem sogenannten geologischen Zeitalter des Menschen, auszuloten. These der Untersuchung ist, dass die performativen Künste im Anthropozän mit den natürlichen, nicht-menschlichen Prozessen untrennbar verbunden sind, und diese Beziehung nicht nur abbilden, sondern in der Bühnenrealität performativ wiederholen. Dieses Verhältnis wird in der Untersuchung mit dem Begriff des anthropozänen Engagements gefasst. Zur Konturierung dieses Begriffs teilt sich die Arbeit in eine theoretisch-normative Voruntersuchung, sowie in die Analyse von ausgewählten Beispielen der zeitgenössischen performativen Künste. Im ersten Teil der Untersuchung wird der Begriff des anthropozänen Engagements über eine Analyse des Diskurses des Anthropozän, seinen Auswirkungen für eine performative Ästhetik sowie über einschlägigen Theorien zum Begriff des Engagements entwickelt. Über die Bestimmung des Anthropozäns als Ereignis, das epistemologische, ontologische und ethische Fragen um den Umgang mit dem Nicht-Menschlichen aufwirft, konstatiert die Untersuchung eine Erweiterung des Geltungsbereiches der performativen Ästhetik. Die veränderte Ausgangsbedingungen der Ästhetik führen dazu, dass die performativen Künste nicht mehr ‚autonom‘ in Hinblick auf die Entwicklungen des Anthropozän sein können. Daher, so schließt die theoretische Voruntersuchung, kann die Beziehung zwischen den performativen Künsten und den nicht-künstlerischen Entwicklungen als anthropozänes Engagement beschrieben werden. Der zweite Teil der Untersuchung gilt sechs Anthroposzenen, künstlerisch-szenischen Anordnungen, in denen das anthropozäne Engagement paradigmatisch aufgezeigt wird. Dabei analysiert die Untersuchung verschiedene Arbeiten der performativen Künste, die seit circa 2000, insbesondere ab 2010 entstanden ist, und verfolgt dabei eine narrative Linie einer schrittweisen Erweiterung des Nicht-Menschlichen. Die Untersuchung zeigt dabei auf, dass die hier präsentierten Arbeiten der performativen Künste über die Problematisierung der Beziehung zwischen Mensch und Nicht-Mensch nicht nur bedeutende Aspekte des Diskurses des Anthropozän in der künstlerischen Realität wiederholen, sondern dass damit auch bestimmte Topoi der Produktion und Rezeption der künstlerischen Praxis selbst hinterfragt werden. Ein anthropozänes Engagement, so argumentiert die Untersuchung folglich, führt über die Problematisierung der Beziehung zwischen Mensch und Nicht-Mensch auch zu einem Umdenken und zu einer Neubestimmung einer performativen Ästhetik.
Weniger anzeigenPolar regions play a critical role in the Earth’s climate system and global nutrient circulation and comprise many different habitats with unique organisms. The seasonal change from the polar night to the midnight sun distinguishes the polar regions from all others of the world. The marine organisms living in these regions have to cope with extreme seasonality of light, temperature, salinity and sea ice. One ecologically particularly important group of eukaryotic microorganisms in polar shallow water coastal zones are benthic diatoms. Diatoms are among the largest and ecologically most successful groups of protists, as they are widespread in almost all aquatic habitats on Earth and contribute significantly to annual carbon fixation. Despite their influential ecological role, there is still little information on their biodiversity in the polar seas. The Diatom Research group of the Botanic Garden and Botanical Museum Berlin in cooperation with the Applied Ecology and Phycology group of the University of Rostock initiated a first study to expand the knowledge about the biodiversity of benthic diatoms in Antarctica by using a combined approach of morphology, culturing and DNA metabarcoding. This project was funded by the Priority Program “Antarctic Research with Comparative Studies in Arctic Ice Regions” of the German Research Foundation. Benthic samples from marine, brackish and freshwater habitats were collected in Potter Cove, King George Island on the Antarctic Peninsula. 162 clonal cultures were successfully established at the Botanic Garden Berlin, resulting in the identification of 60 taxa. A taxonomically validated reference library for Antarctic benthic diatoms with comprehensive information on habitat, morphology and DNA barcodes (rbcL and 18SV4) was created. Three of the most abundant species were Navicula cf. perminuta, Nitzschia annewillemsiana and Navicula gregaria in marine, freshwater and brackish water habitats, respectively. Combining the total morphological richness of 174 taxa, including clones, with an additional 72 taxa assigned by metabarcoding only, resulted in 238 taxa in total. Taxa, which could be assigned on species level showed a high level of endemicity. Finally, all reference sequences were linked to diatom specimens deposited in the Herbarium Berolinense to ensure a complete chain of evidence and further subsequent investigations. The barcode reference library of Antarctic species made it possible to assign 47 taxa in the metabarcoding analyses that could not be assigned previously because no suitable reference sequences were available. Two taxa, Planothidium wetzelii and Chamaepinnularia australis, were newly described within this thesis. The separation of both taxa was only possible by the combined investigation of morphological and molecular traits, which highlights the importance of an integrative taxonomy for diatoms. Chamaepinnularia australis belongs to a genus that is frequently found in the Antarctic and Arctic. Since its first description almost 30 years ago, its position in the diatom tree of life remained uncertain. Molecular phylogeny in combination with the study of morphological features revealed the monophyly of this genus and its allocation to the Sellaphoraceae family. Molecular data are valuable for determining the phylogenetic position of diatom taxa and have proven particularly useful for genera that have been difficult to classify solely based on morphological characters. The clonal diatom cultures have been integrated into the culture collection of the University of Rostock and have been successfully used for ecophysiological studies. The exposure of five strains to total darkness over a period of three months showed that the utilization of storage lipids is one of the key mechanisms in Antarctic benthic diatoms to survive the polar night. Despite an ultrastructural observable degradation of the chloroplast, photosynthetic performance did not change significantly. Further, photosynthesis, respiration, and growth response patterns were investigated as functions of varying light availability, temperature, and salinity in six benthic diatom strains. All of them showed a high ecophysiological plasticity with activity patterns exceeding the environmental range they usually experience in situ. This may represent an important trait to cope with climate change in the Antarctic Peninsula. A thorough taxonomic investigation combined with the evaluation of the biogeographical expansion of a species is required as a baseline for ecophysiological experiments to draw sound conclusions about their adaptation to environmental conditions. To summarise, this project has revealed a remarkably high benthic diatom diversity in the coastal areas of Antarctica. Still, many species are not yet recorded in reference databases. Furthermore, the metabarcoding results indicate a high cryptic diversity with many unassigned taxa even on genus level, which emphasises the need for a further intensive taxonomic investigation of benthic diatom in this region. The genotypic data obtained by DNA barcoding combined with phenotypic information obtained by studying the morphology of marine benthic diatoms are urgently needed to improve our fundamental understanding of the biodiversity and biogeography of diatom communities in the Antarctic. Such data sets not only provide a basis for biodiversity studies, but also for future monitoring programmes, e.g. when investigating the effects of coastal erosion on the benthic diatom flora, for geological questions on the reconstruction of the palaeoenvironment and for the effects of climate change.
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