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Preparing complex jobs for crowdsourcing marketplaces requires careful attention to workflow design, the process of decomposing jobs into multiple tasks, which are solved by multiple workers. Can the crowd help design such workflows? This paper presents Turkomatic, a tool that recruits crowd workers to aid requesters in planning and solving complex jobs. While workers decompose and solve tasks, requesters can view the status of worker-designed workflows in real time; intervene to change tasks and solutions; and request new solutions to subtasks from the crowd. These features lower the threshold for crowd employers to request complex work. During two evaluations, we found that allowing the crowd to plan without requester supervision is partially successful, but that requester intervention during workflow planning and execution improves quality substantially. We argue that Turkomatic's collaborative approach can be more successful than the conventional workflow design process and discuss implications for the design of collaborative crowd planning systems.

Micro-task platforms provide massively parallel, ondemand labor. However, it can be difficult to reliably achieve high-quality work because online workers may behave irresponsibly, misunderstand the task, or lack necessary skills. This paper investigates whether timely, taskspecific feedback helps crowd workers learn, persevere, and produce better results. We investigate this question through Shepherd, a feedback system for crowdsourced work. In a between-subjects study with three conditions, crowd workers wrote consumer reviews for six products they own. Participants in the None condition received no immediate feedback, consistent with most current crowdsourcing practices. Participants in the Self-assessment condition judged their own work. Participants in the External assessment condition received expert feedback. Self-assessment alone yielded better overall work than the None condition and helped workers improve over time. External assessment also yielded these benefits. Participants who received external assessment also revised their work more. We conclude by discussing interaction and infrastructure approaches for integrating real-time assessment into online work.

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The protective bioactivity of punicalagin, a high molecular weight polyphenol isolated from pomegranate fruit pith and carpellary membrane, against oxidative damages to lipids, amino acids constituting the proteins, and guanosine as a model for DNA has been investigated. The ABTS*-, guanosine, and tryptophan radical generated pulse radiolytically were repaired by punicalagin, k = (0.9-15) x 10(7) dm3 mol-1 s-1. The results are rationalized on the basis of the scavenging activity of punicalagin against various one-electron oxidizing radicals, namely, .OH, N3., and NO2. . The formation of the transient species in these reactions and the rate constants of the scavenging reactions have been probed using a time-resolved kinetic spectrophotometric technique. The antioxidant action of punicalagin is expressed not only through its scavenging reactions but also by its ability to form metal chelates. Binding of punicalagin with bovine serum albumin and metal ions such as iron and copper revealed different binding affinities, whereas its binding with DNA was very weak and nonspecific. In vitro cytotoxic studies against three cell lines, namely, Vero (normal African green monkey kidney cell line), Hep-2 (human larynx epithelial cancer cell line), and A-549 (human small cell lung carcinoma cell line) showed that this polyphenol is toxic only at higher concentration.