Study of the epidemiology of Staphylococcus aureus as cause for mastitis in dairy cows and heifers

Deckblatt-Impressum persönlicher Dank Inhaltsverzeichnis Abkürzungsverzeichnis Einleitung Literaturübersicht Material und Methoden Ergebnisse Diskussion Zusammenfassung Summary Literaturverzeichnis Anhang Danksagung SelbständigkeitserklärungDas Ziel der Arbeit war es, mögliche Unterschiede in den Variabilitäten von S. aureus bei Erstkalbinnen und Kühen und zu verschiedenen Probennahmezeitpunkten zu identifizieren. Des weiteren sollte untersucht werden, ob von S. aureus Stämme existieren, die sich epidemiologisch ähnlich wie umweltassoziierte Erreger verhalten. Zuletzt wurde die Frage nach möglichen Risikofaktoren für eine S. aureus Infektion in diese Untersuchung mit einbezogen. Es wurden Anfangsviertelgemelksproben von 359 Deutschen Schwarzbunten Kühen zum Zeitpunkt des Trockenstellens, vor dem ersten Melken nach der Abkalbung sowie in der ersten Woche post partum entnommen. Weiter wurden von 332 Erstkalbinnen vor dem ersten Melken nach der Abkalbung sowie in der ersten und vierten Woche post partum Anfangsviertelgemelksproben gewonnen. Von den gefundenen 234 S. aureus Isolaten wurden 140 mittels Pulsfeld-Gelelektrophorese (Verdau mit smaI) differenziert. In der Herde wurden insgesamt drei klonale Gruppen gefunden (A, B, C), von denen jeweils auch klonale Untergruppen mit nah verwandten Stämmen vorkamen. Es ließ sich weder insgesamt noch zu einem bestimmten Probennahmezeitpunkt ein Zusammenhang zwischen Vorkommen eines Stammes und Alter des Tieres (Erstkalbin oder Kuh) erkennen. Der Verbreitungsmodus umweltassoziierter Erreger der S. aureus Stämme liess sich in dieser Studie nicht beweisen, bestenfalls vermuten. Euter-, Zitzen- und Zitzenkuppenform zeigten in dieser Studie keine Bedeutung als Risikofaktoren für eine S. aureus Infektion. Nur eine mittelgradige Hyperkeratose der Zitzenschleimhaut wies eine signifikant höhere Häufigkeit einer S. aureus Infektion auf. Die mittlere somatische Zellzahl lag bei einer S. aureus Infektion sowohl auf Viertel- als auch auf Tierebene signifikant am höchsten. Eine S. aureus Infektion zeigte in dieser Studie keine Auswirkungen auf mittlere Milchleistung sowie den mittleren Fett- und Eiweißgehalt der Milch.The objective of this study was to evaluate whether the variability of strains of S. aureus that cause intramammary infections differs between dairy cows and heifers. Further it was to evaluate whether S. aureus strains with attributes of environmental pathogens exist. Finally the evaluation of possible risk factors for S. aureus infections was included in this study. Sterile quarter milk samples were taken from 359 German Schwarzbunte dairy cows at time of dry off, at time of calving and in the first week post partum. Further quarter milk samples were taken from 332 heifers at time of calving and in the first and fourth week post partum. 140 of the 234 S. aureus isolates we found were genotyped via PFGE. It turned out that three different clonal groups (A, B, C) were present in the herd. To each group clonal subgroups with closely related strains existed. There was no obvious connection between the occurrence of a certain strain and the parity of the animal (dairy cow or heifer). The spreading pattern of environmental pathogens could not be proved by the S. aureus strains found in this study. At most, it could be assumed. In this study the shape of the udder, teat and teat end were not significantly associated with S. aureus infections. In contrast, the frequency of S. aureus infections was significantly higher in teats with moderate hyperkeratosis. On both quarter and animal level the mean somatic cell count was significantly higher in cases with S. aureus infection. An intramammary infection did not affect the mean milk yield and mean fraction of fat and protein content in this study

Experimental Determination of Elastic and Rupture Properties of Printed Ninjaflex

In this paper, the effect of the 3D printing procedure on the elasticity during fused deposition modeling (FDM) is investigated. The considered material with brand name Ninjaflex is a thermoplastic polyurethane. Uniaxial tension tests are performed to identify the material properties, specifically the Young’s modulus, the maximum stretch, the tensile strength and the material’s fracture toughness. The influence of geometric characteristics on the material properties is studied. From the experimental results the parameters of Ogden’s hyperelastic material model are derived. A finite element simulation of the uniaxial tensile test validates the values obtained from a conditional least-square fit. In conclusion, additional to the experimentally determined rupture properties, the elastic parameters adapted to a Neo-Hookean, a Money-Rivlin and an Ogden material model of Ninjaflex are presented

On the Elastic Modeling of Highly Extensible Polyurea

Polyurea is a soft and highly flexible material commonly used as protective coating on concrete or steel structures. Often subjected to abrasion and impact loading, numerical simulations of such structures require material models accounting for both stiffness and high extensibility of the coating. Hence, comparing several classical approaches with emphasis on efficiency and material stability, for impact simulations a Mooney-Rivlin model with μ1 = 6 MPa and μ2 = 1.5 MPa is suggested. Therefor material parameters from different sources are collected and, additionally, data from our uniaxial tension experiments are provided. The modeling is verified by comparison with a Taylor anvil impact experiment

Materializing design fictions for metaverse services

As the state-of-the-art stands, our knowledge of designing Metaverse platforms is limited. In this paper we propose that design fictions are the first form of prototyping and explore how ‘materializing’ a design fiction can help cement or refute assumptions that drive the development of a software-based system toward a first Minimum Viable Product. Our context is a platform for trading music memorabilia in the Metaverse, integrating content sitting across archives, record labels, publishers, and private collections in an immersive and accessible manner. The design fiction provided both a means of exploring the businessassumptions of our industry partner and co-creating an experience of value to its intended audience. As key outcomes, the approach was of value in shapingbusiness assumptions, developing an enhanced understanding of the audience and allowing them to cocreate, shaping technology needs and identifying partners necessary for the development

Exploring The Impact Of Digital Humans On Customer Experience

This ongoing work focuses on the virtual technology of digital humans, specifically on the potential impacts on customer experience. It starts by introducing the development of a believability framework for digital humans, emphasizing the interactions between behaviour, personality, appearance, and environment to enhance their realism. The framework aims to alleviate the "uncanny valley" effect and improve consumer interaction by making digital humans more lifelike and emotionally intelligent. The study employs a design science research approach, creating digital humans as student ambassadors in a university scenario, and has undergone three iterations, including interviews with university faculty and staff, co-creative workshops with students, and field experiments. The goal is to conduct empirical tests to refine the framework, thus enhancing customer experience in a virtual world environment.<br/

Analysing the preferred characteristics of frontline employees dealing with customer complaints: A cross‐national Kano study

Recent research in customer satisfaction suggests that attributes of products and services can be classified into three categories, must-be factors, one-dimensional factors and excitement factors, which all affect customer satisfaction and dissatisfaction. These originate from Kano’s model (1984) that allows researchers to gain a deeper understanding of customer preferences by analysing how they evaluate and perceive product or service attributes. This paper uses the Kano model to gain a deeper understanding of attributes of effective frontline employees dealing with customer complainants in personal interactions. For products such as the TV remote control, Kano (2001; 2006) showed that excitement factors deteriorate to must-be factors over time. This research investigates whether the same phenomenon holds true for attributes of service employees. Data were collected from 197 respondents with complaining experience in the UK and Saudi Arabia, these being two countries at different stages of service sector development and the analysis of the Kano maps reveal significant differences between the two countries

Minorités et circulations techniques : la confection des armures à Tours (XVe-XVIe siècles)

Aux xve et xvie siècles, Tours apparaît comme un des centres armuriers les plus importants du royaume de France. La présence, à Tours, tout au long de ces deux siècles, d’une importante communauté d’armuriers d’origine étrangère, principalement originaires du nord de la péninsule italienne mais également des Flandres et des terres d’Empire, n’est pas étrangère à ce développement et à cette réputation d’excellence qu’ont acquis les armures fabriquées dans la cité ligérienne. L’immigration de ces artisans spécialisés, issus de dynasties d’armuriers déjà célèbres, a été encouragée par une volonté politique délibérée des souverains français afin de favoriser la diffusion dans le royaume d’un savoir-faire unique. Installés en Touraine, ces armuriers transalpins, allemands ou encore flamands ont bénéficié de statuts privilégiés et de nombreux avantages. Fournisseurs des rois et des grands personnages du royaume, ils ont su s’intégrer parfaitement au reste de la communauté, et ont contribué, par le biais de leurs apprentis, à pérenniser l’art dont ils étaient dépositaires.In the fifteenth and sixteenth centuries, Tours was one of the biggest armour making centres in the kingdom of France. The long-lasting presence of a large community of armour makers of foreign origins, mostly from the North of Italy but also from the Flanders and the German Empire, was a main reason to the development and the reputation of excellence gained by the armours made up in the city. The immigration of these skilled artisans, belonging to dynasties of famous armour makers, was encouraged by the deliberate political will of the French sovereigns, who wanted to ease the diffusion of this original art in the kingdom. Now settled in Touraine, these Italian, German or Flemish armour makers were privileged with special statuses. As suppliers of the king and of the highest dignitaries of the kingdom, they became perfectly integrated to the community, and they contributed, through the apprentices they taught, to make the high skills they possessed, a well established art