Die Besiedelung einer neugepflanzten Feldhecke durch epigäische Spinnen (Arachnida: Araneae) : ein ökofaunistischer Beitrag zur Kenntnis von Spinnenzönosen agrarwirtschaftlicher Intensivflächen (Schwand im Innkreis, Bezirk Braunau, Oberösterreich)

In einer im Rahmen der Förderaktion "Grüne Welle" neugepflanzten Feldhecke wurde die Besiedelungsdynamik epigäischer Spinnen während der ersten Vegetationsperiode untersucht. Die Initialpflanzung mit standorttypischen Strauchgehölzen und Bäumen erfolgte im Oktober 1992 auf agrarwirtschaftlich intensiv genutzten Flächen bei Schwand im Innkreis (Bezirk Braunau, Oberösterreich). Der 380 m lange und 3.5 m breite Anpflanzungsstreifen ist in vier unterschiedlich große Abschnitte unterteilt, die durch brachliegende Ackerstreifen getrennt sind. Die Abschnitte variieren hinsichtlich der Flächengröße, aber auch hinsichtlich der angrenzenden Agrarflächen, weswegen zwischen einem beiderseitig an Getreidefelder (Sommerhafer-, Wintergerstenfeld) grenzenden Teilbereich I und einem auf der einen Seite an eine dreihmahdige Fettwiese und auf der anderen Seite an ein Sommerhaferfeld grenzenden Teilbereich I unterschieden wird

Delivery of ready-mixed concrete in a dynamic environment

Das Thema dieser Magisterarbeit behandelt die Auslieferung von Fertigbeton in einem dynamischen Umfeld. Das Ziel der Arbeit ist mit einem bestehenden Algorithmus eine Laufzeit-Analyse durchzuführen. Die Auslieferung von Fertigbeton stellt eine logistische Herausforderung dar und wird in der Literatur durch ein VRP (Vehicle Routing Problem) beschrieben. Ein VRP, in diesem Fall mit unterschiedlichen Bedingungen, ist eines der schwierigsten Aufgabenstellungen aus dem Bereich der Kombinatorik. Mit Hilfe des Algorithmus kann das VRP jedoch fast optimal gelöst werden, gleichzeitig verbessert sich auch die Lösung über einem längeren Zeitraum. Anhand von drei unterschiedlichen Experimenten soll die Anwendbarkeit und Lösungsgüte des Algorithmus untersucht werden. Dabei werden verschiedene Auftragsszenarien unter statischen, dynamischen bzw. hypothetischen Bedingungen generiert. Der Fokus liegt in der Reaktionsfähigkeit des Algorithmus und den damit verbundenen Auswirkungen auf den Planungsprozess. Die Arbeit besteht aus drei Hauptteilen. Der erste Teil befasst sich mit dem theoretischen Hintergrund. Der zweite Abschnitt beschreibt die spezifischen Eigenschaften und Anforderungen an Fertigbeton. Zum Abschluss der Arbeit werden die drei Experimente genauer beschrieben und die Ergebnisse präsentiert.This thesis deals with the delivery of ready-mixed concrete in a dynamic environment. Its aim is a run time analysis of a certain algorithm which is used for vehicle routing problems, a problem which is in the field of combinatorial optimization problems one of the most challenging ones, which can not only solve this problem to near-optimality, but also improves the given solution over time. For this case the algorithm is applied on three generated experiments set in a static/dynamic environment. The focus lies upon the reaction of the algorithm and on the consequences for the schedulers who have to deal with this matters which often occur on short notice. The thesis consists of three main parts. The first part takes a deeper look at the theory behind this problem. Two combinatorial optimization problems have been explained, and their solutions methods were presented. Then the material itself was presented, its special features and how this inflicts the production system and delivery of ready-mixed concrete. The last part consists of the experiments and the results of the study

"Ich bin Wahrnehmungsfachmann"

Diese Diplomarbeit beschäftigt sich mit asylrichterlichen Wahrnehmungen von Gender und Kultur. Dazu wurden Interviews mit RichterInnen, informelle Gespräche und Beobachtungen von Asylverhandlungen am Asylgerichtshof in Wien sowie dessen Außenstelle in Linz durchgeführt. Über bestimmte Wahrnehmungen von Kultur eröffnet sich ein Spannungsfeld zwischen bemühter Kultursensibilität und vereinfachten Kulturalisierungen. So werden verschiedene (hierarchisierte) Formen von Gender beispielsweise über ihre gedachten kulturellen Merkmale definiert. Gender wird zur Fläche, auf der Kultur sichtbar ist. Es soll ein Eindruck davon vermittelt werden, wie RichterInnen versuchen, Glaubwürdigkeit festzustellen. Von RichterInnen dazu genannte Glaubwürdigkeitskriterien werden aufgezeigt und in ihrer Entstehung analysiert. Diesbezüglich geht es nicht nur um die „fremde“, sondern oft vielmehr um die „eigene“ Strukturiertheit der RichterInnen, wobei in Anlehnung an Rousseau et al. (Rousseau et al.2002) eine „culture of disbelief“ zur Diskussion gestellt wird. Aus diesem Grund ist ein Ansatzpunkt wichtig, der Interpretationsleistungen und Emotionen der RichterInnen miteinbezieht und die Auswirkungen dieser Emotionen auf Entscheidungen und mögliche Entscheidungsgrundlagen thematisiert. Weiters zeigen sich verschiedene Tendenzen, stereotype Bilder als Entscheidungshilfe zu formulieren, sowie Gegenstrategien zu dieser Praxis. Die Thematisierung von Krisensituationen im Gerichtssaal beleuchtet zusätzlich stark hierarchisierte Verhandlungssituationen, in denen soziale Geschlechterkonstruktionen eine wesentliche Rolle in der Herstellung, Krisenhaftigkeit und Verteidigung dieser Hierarchie spielen. Als roter Faden der Arbeit wird beschrieben, wie EntscheidungsträgerInnen bestimmte Diskurse wählen oder versuchen, diese zu umgehen. Dies eröffnet nicht nur Raum für Kritik, sondern erlaubt auch Reflexion und Veränderung bestimmter Handlungs- und Interpretationsfelder

T cells can mediate viral clearance from ependyma but not from brain parenchyma in a major histocompatibility class I- and perforin-independent manner

Viral infection of the central nervous system can lead to disability and death. Yet the majority of viral infections with central nervous system involvement resolve with only mild clinical manifestations, if any. This is generally attributed to efficient elimination of the infection from the brain coverings, i.e. the meninges, ependyma and chorioplexus, which are the primary targets of haematogeneous viral spread. How the immune system is able to purge these structures from viral infection with only minimal detrimental effects is still poorly understood. In the present work we studied how an attenuated lymphocytic choriomeningitis virus can be cleared from the central nervous system in the absence of overt disease. We show that elimination of the virus from brain ependyma, but not from brain parenchyma, could be achieved by a T cell-dependent mechanism operating independently of major histocompatibility class I antigens and perforin. Considering that cytotoxic T lymphocyte-mediated cytotoxicity is a leading cause of viral immunopathology and tissue damage, our findings may explain why the most common viral intruders of the central nervous system rarely represent a serious threat to our healt

Secreted IgM deficiency leads to increased BCR signaling that results in abnormal splenic B cell development.

Mice lacking secreted IgM (sIgM -/-) antibodies display abnormal splenic B cell development, which results in increased marginal zone and decreased follicular B cell numbers. However, the mechanism by which sIgM exhibit this effect is unknown. Here, we demonstrate that B cells in sIgM -/- mice display increased B cell receptor (BCR) signaling as judged by increased levels of phosphorylated Bruton's tyrosine kinase (pBtk), phosphorylated Spleen tyrosine kinase (pSyk), and nuclear receptor Nur77. Low dosage treatment with the pBtk inhibitor Ibrutinib reversed the altered B cell development in the spleen of sIgM -/- mice, suggesting that sIgM regulate splenic B cell differentiation by decreasing BCR signaling. Mechanistically, we show that B cells, which express BCRs specific to hen egg lysozyme (HEL) display diminished responsiveness to HEL stimulation in presence of soluble anti-HEL IgM antibodies. Our data identify sIgM as negative regulators of BCR signaling and suggest that they can act as decoy receptors for self-antigens that are recognized by membrane bound BCRs

Innate and adaptive immune control of genetically engineered live-attenuated arenavirus vaccine prototypes

Arenaviruses such as Lassa virus (LASV) cause significant morbidity and mortality in endemic areas. Using a glycoprotein (GP) exchange strategy, we have recently developed live-attenuated arenavirus vaccine prototypes (rLCMV/VSVG) based on lymphocytic choriomeningitis virus (LCMV), a close relative of LASV. rLCMV/VSVG induced long-term CD8+ T cell immunity against wild-type virus challenge and exhibited a stably attenuated phenotype in vivo. Here we elucidated the innate and adaptive immune requirements for the control of rLCMV/VSVG. Infection of RAG−/− mice resulted in persisting viral RNA in blood but not in overt viremia. The latter was only found in mice lacking both RAG and IFN type I receptor. Conversely, absence of IFN type II signaling or NK cells on an RAG-deficient background had only minor effects on vaccine virus load or none at all. rLCMV/VSVG infection of wild-type mice induced less type I IFN than did wild-type LCMV, and type I as well as type II IFNs were dispensable for the induction of virus-specific memory CD8 T cells and virus-neutralizing antibodies by rLCMV/VSVG. In conclusion, the adaptive immune systems are essential for elimination of rLCMV/VSVG, and type I but not type II IFN plays a major contributive role in lowering rLCMV/VSVG loads in vivo, attesting to the attenuation profile of the vaccine. Nevertheless, IFNs are not required for the induction of potent vaccine responses. These results provide a better understanding of the immunobiology of rLCMV/VSVG and will contribute to the further development of GP exchange vaccines for combating arenaviral hemorrhagic fever

Protective Efficacy of Individual CD8+ T Cell Specificities in Chronic Viral Infection.

Specific CD8(+) T cells (CTLs) play an important role in resolving protracted infection with hepatitis B and C virus in humans and lymphocytic choriomeningitis virus (LCMV) in mice. The contribution of individual CTL specificities to chronic virus control, as well as epitope-specific patterns in timing and persistence of antiviral selection pressure, remain, however, incompletely defined. To monitor and characterize the antiviral efficacy of individual CTL specificities throughout the course of chronic infection, we coinoculated mice with a mixture of wild-type LCMV and genetically engineered CTL epitope-deficient mutant virus. A quantitative longitudinal assessment of viral competition revealed that mice continuously exerted CTL selection pressure on the persisting virus population. The timing of selection pressure characterized individual epitope specificities, and its magnitude varied considerably between individual mice. This longitudinal assessment of "antiviral efficacy" provides a novel parameter to characterize CTL responses in chronic viral infection. It demonstrates remarkable perseverance of all antiviral CTL specificities studied, thus raising hope for therapeutic vaccination in the treatment of persistent viral diseases

Envelope Exchange for the Generation of Live-Attenuated Arenavirus Vaccines

Arenaviruses such as Lassa fever virus cause significant mortality in endemic areas and represent potential bioterrorist weapons. The occurrence of arenaviral hemorrhagic fevers is largely confined to Third World countries with a limited medical infrastructure, and therefore live-attenuated vaccines have long been sought as a method of choice for prevention. Yet their rational design and engineering have been thwarted by technical limitations. In addition, viral genes had not been identified that are needed to cause disease but can be deleted or substituted to generate live-attenuated vaccine strains. Lymphocytic choriomeningitis virus, the prototype arenavirus, induces cell-mediated immunity against Lassa fever virus, but its safety for humans is unclear and untested. Using this virus model, we have developed the necessary methodology to efficiently modify arenavirus genomes and have exploited these techniques to identify an arenaviral Achilles' heel suitable for targeting in vaccine design. Reverse genetic exchange of the viral glycoprotein for foreign glycoproteins created attenuated vaccine strains that remained viable although unable to cause disease in infected mice. This phenotype remained stable even after extensive propagation in immunodeficient hosts. Nevertheless, the engineered viruses induced T cell–mediated immunity protecting against overwhelming systemic infection and severe liver disease upon wild-type virus challenge. Protection was established within 3 to 7 d after immunization and lasted for approximately 300 d. The identification of an arenaviral Achilles' heel demonstrates that the reverse genetic engineering of live-attenuated arenavirus vaccines is feasible. Moreover, our findings offer lymphocytic choriomeningitis virus or other arenaviruses expressing foreign glycoproteins as promising live-attenuated arenavirus vaccine candidates

Characterization of host proteins interacting with the lymphocytic choriomeningitis virus L protein

RNA-dependent RNA polymerases (RdRps) play a key role in the life cycle of RNA viruses and impact their immunobiology. The arenavirus lymphocytic choriomeningitis virus (LCMV) strain Clone 13 provides a benchmark model for studying chronic infection. A major genetic determinant for its ability to persist maps to a single amino acid exchange in the viral L protein, which exhibits RdRp activity, yet its functional consequences remain elusive. To unravel the L protein interactions with the host proteome, we engineered infectious L protein-tagged LCMV virions by reverse genetics. A subsequent mass-spectrometric analysis of L protein pulldowns from infected human cells revealed a comprehensive network of interacting host proteins. The obtained LCMV L protein interactome was bioinformatically integrated with known host protein interactors of RdRps from other RNA viruses, emphasizing interconnected modules of human proteins. Functional characterization of selected interactors highlighted proviral (DDX3X) as well as antiviral (NKRF, TRIM21) host factors. To corroborate these findings, we infected Trim21-/-mice with LCMV and found impaired virus control in chronic infection. These results provide insights into the complex interactions of the arenavirus LCMV and other viral RdRps with the host proteome and contribute to a better molecular understanding of how chronic viruses interact with their host

Immunometabolism pathways as the basis for innovative anti-viral strategies (INITIATE): a Marie Sklodowska-Curie innovative training network

The past century has witnessed major advances in the control of many infectious diseases, yet outbreaks and epidemics caused by (re-) emerging RNA viruses continue to pose a global threat to human health. As illustrated by the global COVID19 pandemic, high healthcare costs, economic disruption and loss of productivity reinforce the unmet medical need to develop new antiviral strategies to combat not only the current pandemic but also future viral outbreaks. Pivotal for effective anti-viral defense is the innate immune system, a first line host response that senses and responds to virus infection. While molecular details of the innate immune response are well characterized, this research field is now being revolutionized with the recognition that cell metabolism has a major impact on the antiviral and inflammatory responses to virus infections. A detailed understanding of the role of metabolic regulation with respect to antiviral and inflammatory responses, together with knowledge of the strategies used by viruses to exploit immunometabolic pathways, will ultimately change our understanding and treatment of pathogenic viral diseases. INITIATE is a Marie Sklodowska-Curie Actions Innovative Training Network (MSCA-ITN), with the goal to train 15 early stage PhD researchers (ESRs) to become experts in antiviral immunometabolism (https://initiate-itn.eu/). To this end, INITIATE brings together a highly complementary international team of academic and corporate leaders from 7 European countries, with outstanding track records in the historically distinct research fields of virology, immunology and metabolism. The ESRs of INITIATE are trained in these interdisciplinary research fields through individual investigator-driven research projects, specialized scientific training events, workshops on academia-industry interactions, outreach & communication. INITIATE will deliver a new generation of creative and entrepreneurial researchers who will be able to face the inevitable future challenges in combating viral diseases