I Scratched Yours: The Prevalence of Reciprocation in Feedback Provision on eBay

Many online systems for bilateral transactions elicit performance feedback from both transacting partners. Such bilateral feedback giving introduces strategic considerations. We focus on reciprocity in the giving of feedback: how prevalent a strategy of giving feedback is only if feedback is first received from one’s trading partner. The overall level of feedback activity clearly depends on the prevalence of the reciprocation strategy: in a market with many reciprocators and few unconditional feedback providers, the equilibrium quantity of feedback can be quite low. We estimate the prevalence of such reciprocation in one market, eBay. Reciprocation cannot be directly distinguished from late feedback that was not conditioned on the partner having provided feedback. We develop a model that distinguishes the two by exploiting information about the timing of feedback provision when the partner does not provide feedback. We find that buyers and sellers on eBay used the “reciprocate only” strategy about 20-23% of the time. We also measure the extent to which the prevalence of these strategies changes with the experience levels of the two parties and with the item price.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78401/1/prevalence_of_reciprocation.pd

Why Do Countries and Industries with Large Seasonal Cycles Also Have Large Business Cycles?

We show there is a strong, positive correlation across countries and industries between the standard deviation of the seasonal component and the standard deviation of the non-seasonal component of aggregate variables such as output, labor input, interest rates, and prices. After documenting this stylized fact, we discuss possible explanations and develop a model that generates our empirical finding. The main feature of the model is that firms endogenously choose their degree of technological flexibility as a function of the amounts of seasonal and non-seasonal variation in demand. Although this model is intended to be illustrative, we find evidence supporting one of its key empirical implications.

Pecking order theory versus trade-off theory : are service SMEs’ capital structure decisions different?

This paper seeks to analyse if the capital structure decisions of service small and medium-sized enterprises (SMEs) are different from those of other types of firm. To do so, we consider four research samples: (i) 610 service SMEs; (ii) 126 service large firms; (iii) 679 manufacturing and construction SMEs; and (iv) 132 manufacturing and construction large firms. Using the two-step estimation method, the empirical evidence obtained in this study shows that the capital structure decisions of service SMEs are different from those of other types of firm. Service SMEs’ capital structure decisions are closer to the assumptions of Pecking Order Theory and further removed from those of Trade-Off Theory compared with the case of other types of firm

Social participation for older people with aphasia: The impact of communication disability on friendships

Purpose: The language changes experienced by a person with aphasia following a stroke often have sudden and long-lasting negative impact on friendships. Friendship relationships are core to social engagement, quality of life, and emotional well-being. The aims of this study were to describe everyday communication with friends for older people with and without aphasia and to examine the nature of actual friendship conversations involving a person with aphasia. Method: This naturalistic inquiry drew data from two phases of research: a participant observation study of 30 older Australians, 15 of whom had aphasia following a stroke, and a collective case study using stimulated recall to examine friendship conversations involving an older person with aphasia. Results: People with aphasia communicated with fewer friends and had smaller social networks. "Friendship" was a core domain of communication for older people and participation in leisure and educational activities was focal in everyday communication with friends. Case study data of conversations between three older people with aphasia and their friends illuminated features of "time," the role of humour, and friends having shared interests. Conclusion: Aphasia has been found to impact on friendships. A need exists for research and intervention programs to address communication with friends for older people with aphasia

Kidney Development in the Absence of Gdnf and Spry1 Requires Fgf10

GDNF signaling through the Ret receptor tyrosine kinase (RTK) is required for ureteric bud (UB) branching morphogenesis during kidney development in mice and humans. Furthermore, many other mutant genes that cause renal agenesis exert their effects via the GDNF/RET pathway. Therefore, RET signaling is believed to play a central role in renal organogenesis. Here, we re-examine the extent to which the functions of Gdnf and Ret are unique, by seeking conditions in which a kidney can develop in their absence. We find that in the absence of the negative regulator Spry1, Gdnf, and Ret are no longer required for extensive kidney development. Gdnf−/−;Spry1−/− or Ret−/−;Spry1−/− double mutants develop large kidneys with normal ureters, highly branched collecting ducts, extensive nephrogenesis, and normal histoarchitecture. However, despite extensive branching, the UB displays alterations in branch spacing, angle, and frequency. UB branching in the absence of Gdnf and Spry1 requires Fgf10 (which normally plays a minor role), as removal of even one copy of Fgf10 in Gdnf−/−;Spry1−/− mutants causes a complete failure of ureter and kidney development. In contrast to Gdnf or Ret mutations, renal agenesis caused by concomitant lack of the transcription factors ETV4 and ETV5 is not rescued by removing Spry1, consistent with their role downstream of both RET and FGFRs. This shows that, for many aspects of renal development, the balance between positive signaling by RTKs and negative regulation of this signaling by SPRY1 is more critical than the specific role of GDNF. Other signals, including FGF10, can perform many of the functions of GDNF, when SPRY1 is absent. But GDNF/RET signaling has an apparently unique function in determining normal branching pattern. In contrast to GDNF or FGF10, Etv4 and Etv5 represent a critical node in the RTK signaling network that cannot by bypassed by reducing the negative regulation of upstream signals