Curbing customer-to-customer misbehavior contagion in the sharing economy

The sharing economy has fundamentally transformed customers’ lives. Providing short-term access to resources, however, creates environments in which customers regularly become the target of other customers’ misbehavior, either personally or toward shared resources. Although this customer-to-customer (C2C) misbehavior is known to be contagious, the reasons for its spread and the effectiveness of containment measures across sharing economy markets remain unclear. Three experiments reveal the moderating role of on-site supervision: platform-provider-directed blame attributions drive C2C misbehavior contagion in settings with formal on-site supervision, while social norms underlie contagion when on-site supervision is absent. Perpetrator-directed blame attributions reverse contagion irrespective of on-site supervision. More intrusive platform and peer-provider measures (in-person reprimands, in-app messages, and photo features) are most effective at curbing contagion by reducing social norms to misbehave and shifting blame to the perpetrator. However, these measures are only effective at certain C2C misbehavior severity levels for different sharing economy market types

Space shuttle high pressure auxiliary propulsion subsystem definition study. Design handbook

Space shuttle high pressure, hydrogen oxygen auxiliary propulsion subsystem designs, weight sensitivities, and operating performance

Experimentelle Untersuchungen zum Einfluss von Eicosapentaensäure versus Arachidonsäure auf die Immunantwort polymorphkerniger neutrophiler Granulozyten in einem Koinkubationsmodell von Granulozyten und Endothelzellen

Hintergrund: Die Interaktion von Polymorphkernigen Neutrophilen Granulozyten (PMN) und Endothelzellen (EC) spielt eine zentrale Rolle in der Pathogenese vieler inflammatorischer Erkrankungen. Von besonderer Bedeutung sind dabei die Wirkungen der Lipidmediatoren, die aus der mehrfach ungesättigten Fettsäure Arachidonsäure (C20:4, w-6) synthetisiert werden. Ausgehend von der Notwendigkeit parenteraler Zufuhr von Lipiden bei schwerstkranken Patienten und dem Wissen um die proinflammatorischen Wirkungen der darin enthaltenen Arachidonsäure (AA) sollte in der vorliegenden Arbeit die Wirkung einer alternativen Fettsäure, der aus Fischölen gewonnenen w-3-Fettsäure Eicosapentaensäure (EPA, C20:5), untersucht werden. Methode: An einem Modell der parenteralen Fettsäurezufuhr mit aus Nabelschnüren gewonnenen Endothelzellen (HUVEC) und isolierten humanen PMN sollte geprüft werden, ob Endothelzellen angebotene freie Fettsäuren innerhalb kurzer Zeit in ihre Phospholipidpools aufnehmen, und ob sich die Fettsäurezufuhr auf eine spätere Koinkubation mit Granulozyten im Hinblick auf deren Immunantwort auswirkt. Des weiteren wurden Ansätze untersucht, die eine Erklärung für die Modulation der Immunantwort liefern könnten. Als Parameter zur Erfassung der Immunantwort der Granulozyten dienten Leukotriene als Lipidmediatoren, Elastase als proteolytisches Enzym bei Degranulationsreaktionen, sowie die Adhärenz von PMN an EC und die Bildung von Second-Messenger-Produkten durch PMN. Die Zellen wurden in vitro isoliert, koinkubiert und mit einem Calcium-Ionophor stimuliert. Ergebnisse: Sowohl bei der Elastase- als auch bei der Leukotrienproduktion der Granulozyten konnte die antiinflammatorische Wirkung der EPA gezeigt werden. Zusammen mit dem Auftreten der von EPA abgeleiteten von den Granulozyten produzierten Lipidmediatoren zeigt dies die effektive Aufnahme von EPA durch die Endothelzellen und deren Bereitstellung bei darauffolgender Stimulation. Dies konnte noch erhärtet werden durch die Hemmung der Phospholipase A2 der Endothelzellen, die den positiven Effekt der EPA teilweise wieder aufhob. Demgegenüber blieb eine Inhibition der Cyclooxygenase weitgehend ohne Effekt. Des weiteren konnte die Herabsetzung der Adhärenz von PMN an EPA-gefütterten Endothelzellen nachgewiesen werden. Die Erfassung der Second-Messenger-Bildung anhand der Inositolphosphatproduktion sollte den Einfluß von EPA auf die Signaltransduktion in der Zelle klären. Hier zeigte sich eine Modulation der Signalantwort von PMN im Sinne einer verzögerten Bildung von Inositolphosphaten. Fazit: Die Ergebnisse zeigen, daß die parenterale Zufuhr von Lipidemulsionen auf Basis von w-3-Fettsäuren eine hemmende Wirkung auf inflammatorische Prozesse im Organismus haben kann, da EPA von Endothelzellen innerhalb kurzer Zeit gespeichert wird und dadurch die Immunantwort von endotheladhärenten PMN beeinflußt.Background: The interaction between Granulocytes (PMN) and endothelial cells (EC) is a critical step in the pathogenesis of many inflammatory diseases. Especially lipid mediators, which are metabolised from arachidonic acid (AA, C20:4, n-6), play an important role in this setting. As infusion of lipid emulsions (which contain AA) is necessary in many critically ill patients, the effects of an alternative fatty acid, the n-3 fatty acid eicosapentaenoic acid (C20:5) from fish oils were investigated. Methods: In an model of parenteral application of free fatty acids, human umbilical vein derived endothelial cells (HUVEC) were incubated with either AA or EPA, then coincubated with isolated human PMN and stimulated with a calcium-ionophore. The aim was to clarify whether free fatty acids are incorporated into endothelial phopholipidpools within a short period of time (2h) and exert different effects on the immune response of coincubated PMN later on. As parameters of the immune response served: the activity elastase as a proteolytic enzyme in degranulation reactions, generation of leukotrienes as lipid mediators, adhesion of PMN on EC, and generation of second messenger products. Furthermore, cyclooxygenase and phospholipase A2 respectively were inhibited to investigate their possible influence on the immunomodulatory effects of n-3 fatty acids. Results:The antiinflammatory effects of eicosapentaenoic acid were demonstrated both in reduced lipid mediator generation and elastase activity, together with the appearance of EPA-derived leukotrienes. Adhesion of PMN on EC was significantly reduced after application of EPA, and the generation of second messenger products was delayed. Inhibition of phospholipase A2 cancelled these effects, whereas inhibition of cyclooxygenase showed no effect. Conclusion:Parenteral application of n-3 lipid emulsions could be an effective way to modulate the immune response of PMN, as free EPA is incorporated into endothelial phospholipidpools within a few hours and effects lipid mediator generation and elastase activity of PMN, adhesion of PMN on EC and signaltransduction in PMN

Cold-Formed Steel Examples to the Theory and Finite Element Implementation of Plasticity

This paper presents two examples to the theory and finite element implementation of plasticity. The first example is on the cross-sectional behavior of trapezoidal sheeting subjected to a concentrated load. It is shown that the number of elements (and thus the number of integration points) along the comer radius are important for the correct modeling of this static problem. The second example is on the failure of first-generation sheeting subjected to a concentrated load and a bending moment. This problem, especially for large span lengths, can be solved only with explicit dynamic simulations. These are, for our research field, for the first time published here. The explicit simulations normally function with a rather simple integration scheme for plasticity; is shown that our sheeting results are very sensitive to this

Cold-Formed Steel Examples to the Theory and Finite Element Implementation of Plasticity

This paper presents two examples to the theory and finite element implementation of plasticity. The first example is on the cross-sectional behavior of trapezoidal sheeting subjected to a concentrated load. It is shown that the number of elements (and thus the number of integration points) along the comer radius are important for the correct modeling of this static problem. The second example is on the failure of first-generation sheeting subjected to a concentrated load and a bending moment. This problem, especially for large span lengths, can be solved only with explicit dynamic simulations. These are, for our research field, for the first time published here. The explicit simulations normally function with a rather simple integration scheme for plasticity; is shown that our sheeting results are very sensitive to this

Mobile Micro-X-ray Fluorescence Analysis (XRF) on Medieval Paintings

X-ray fluorescence has long been applied to objects of art and archaeology for non-destructive elemental analysis. When the object under investigation is either too big or too fragile to be moved a mobile instrument is needed which can be brought on site. A short overview of the development of techniques and applications shall be given in the paper. Then three case studies are reported in which ArtTax/Artax spectrographs were applied for the analysis of medieval paintings. Experimental issues are discussed with respect to the application to paintings as well

Introduction to the Theory and Finite Element Implementation of (Steel) Plasticity

This paper tries to enlighten the subject of (numerical) plasticity by presenting fundamental theory and some very practical examples. For a two-dimensional plain stress state, a Hubert-Henky yield criterion is derived. The flow rule is discussed, including an explanatory numerical example. The yield criteria and flow rule are theoretically applied in a four node finite element. This element is used to show some of the conditions and limitations of a plastic calculation in the finite element method. Finally, a real finite element calculation is made for illustrating the theory derived

The madwoman in the refrigerator and A Song of Ice and Fire.

There is an existing trope in the fantasy genre I call the madwoman in the refrigerator—in which a female character is killed, maimed, raped, depowered, and/or made to go mad or insane when she is no longer able to uphold the conventional genre expectations of her role in the narrative, such as the angel, monster, or angelic monster. It is a combination of the theory from Sandra Gilbert and Susan Gubar that women are demure angels when they are fulfilling stereotypical feminine roles in a narrative and when desire or agency is found, the woman is a monster, portrayed as a villain or a madwoman to be locked in an attic, and the theory from Gail Simone that women in comics are brutalized and killed in order to create an inciting incident for a male’s plot. Daenerys from George R. R. Martin’s A Song of Ice and Fire and HBO’s Game of Thrones embodies the madwoman in the refrigerator trope, both in how she aligns with the other female angels/monsters and the hero of the story, Jon Snow. After using Dany to prove that the trope exists, I then use her role in the narrative to expose the social problems with the trope and why it is necessary for the fantasy genre to adapt to modern times