On Online Collaboration and Construction of Shared Knowledge: Assessing Mediation Capability in Computer Supported Argument Visualization Tools

Collaborative Computer-Supported Argument Visualization (CCSAV) has often been proposed as an alternative over more conventional, mainstream platforms for online discussion (e.g., online forums and wikis). CCSAV tools require users to contribute to the creation of a joint artifact (argument map) instead of contributing to a conversation. In this paper we assess empirically the effects of this fundamental design choice and show that the absence of conversational affordances and socially salient information in representation-centric tools is detrimental to the users' collaboration experience. We report empirical findings from a study in which subjects using different collaborative platforms (a forum, an argumentation platform, and a socially augmented argumentation tool) were asked to discuss and predict the price of a commodity. By comparing users' experience across several metrics we found evidence that the collaborative performance decreases gradually when we remove conversational interaction and other types of socially salient information. We interpret these findings through theories developed in conversational analysis (common ground theory) and communities of practice and discuss design implications. In particular, we propose balancing the trade-off between knowledge reification and participation in representation-centric tools with the provision of social feedback and functionalities supporting meaning negotiation

Pink nodule of the chin: an unusual presentation of metastatic carcinoma

Renal cell carcinoma (RCC) is the most lethal urological tumor, often because it is widely metastasized at the time of diagnosis. There are reports of cutaneous metastases, most commonly to the head and neck, presenting late after RCC is diagnosed. This case presentation explores a 45-year old female patient with a growing skin lesion on her chin, previously treated as an epidermoid cyst before presenting to dermatology clinic. We present a case of cutaneous metastatic clear cell renal cell carcinoma presenting 7 years after initial diagnosis