Worker Retention, Response Quality, and Diversity in Microtask Crowdsourcing: An Experimental Investigation of the Potential for Priming Effects to Promote Project Goals

Online microtask crowdsourcing platforms act as efficient resources for delegating small units of work, gathering data, generating ideas, and more. Members of research and business communities have incorporated crowdsourcing into problem-solving processes. When human workers contribute to a crowdsourcing task, they are subject to various stimuli as a result of task design. Inter-task priming effects - through which work is nonconsciously, yet significantly, influenced by exposure to certain stimuli - have been shown to affect microtask crowdsourcing responses in a variety of ways. Instead of simply being wary of the potential for priming effects to skew results, task administrators can utilize proven priming procedures in order to promote project goals. In a series of three experiments conducted on Amazon’s Mechanical Turk, we investigated the effects of proposed priming treatments on worker retention, response quality, and response diversity. In our first two experiments, we studied the effect of initial response freedom on sustained worker participation and response quality. We expected that workers who were granted greater levels of freedom in an initial response would be stimulated to complete more work and deliver higher quality work than workers originally constrained in their initial response possibilities. We found no significant relationship between the initial response freedom granted to workers and the amount of optional work they completed. The degree of initial response freedom also did not have a significant impact on subsequent response quality. However, the influence of inter-task effects were evident based on response tendencies for different question types. We found evidence that consistency in task structure may play a stronger role in promoting response quality than proposed priming procedures. In our final experiment, we studied the influence of a group-level priming treatment on response diversity. Instead of varying task structure for different workers, we varied the degree of overlap in question content distributed to different workers in a group. We expected groups of workers that were exposed to more diverse preliminary question sets to offer greater diversity in response to a subsequent question. Although differences in response diversity were revealed, no consistent trend between question content overlap and response diversity prevailed. Nevertheless, combining consistent task structure with crowd-level priming procedures - to encourage diversity in inter-task effects across the crowd - offers an exciting path for future study

Incoming and disappearing solutions for Maxwell's equations

We prove that in contrast to the free wave equation in $\R^3$ there are no incoming solutions of Maxwell's equations in the form of spherical or modulated spherical waves. We construct solutions which are corrected by lower order incoming waves. With their aid, we construct dissipative boundary conditions and solutions to Maxwell's equations in the exterior of a sphere which decay exponentially as $t \to +\infty$. They are asymptotically disappearing. Disappearing solutions which are identically zero for $t \geq T > 0$ are constructed which satisfy maximal dissipative boundary conditions which depend on time $t$. Both types are invisible in scattering theory

Challenges for the Evaluation of the P.I.P.P.I. - Programme of Intervention for Prevention of Institutionalisation: between Partecipative and Experimental Pathways

Evaluation is constantly requested by governments and decision-makers, to prove that social policies and actions undertaken are effective in responding to problems. Also programmes contrasting child neglect are involved in such request to guarantee that children enjoy their childhood and ensure access to quality service. This paper focuses on an Italian evaluation experience of one such programme named the P.I.P.P.I. (Programme of Intervention for Prevention of Institutionalisation), the outcome of a collaboration between the University of Padua and the Italian Ministry of Welfare. The paper questions and challenges the experimental designs normally used for these evaluation purposes, highlighting how knowledge of effective treatments is far from the practices delivered. The study proposes an innovative evaluation path in which the participative evaluation, where the professionals build their own knowledge through an evaluation in the field, coexists with the choice of matching as a (quasi) experimental evaluation, responding to the Government\u2019s request for effective investments

Differential Equations with singular fields

This paper investigates the well posedness of ordinary differential equations and more precisely the existence (or uniqueness) of a flow through explicit compactness estimates. Instead of assuming a bounded divergence condition on the vector field, a compressibility condition on the flow (bounded jacobian) is considered. The main result provides existence under the condition that the vector field belongs to $BV$ in dimension 2 and $SBV$ in higher dimensions

P.I.P.P.I.: What has changed? How and why? The empirical evidence

This paper provides a summary of the results of the P.I.P.P.I. Program in achieving the prefixed goals on the final, intermediate and proximal outcome variables, regarding children\u2019s development, the positive exercise of parental competences and the effective action of services respectively. Therefore, the main purpose is to describe the impact of the program on the overall well-being of children and families in relation to the processes implemented. This is possible thanks to the wealth of information gathered by professionals through the tools provided for the analysis, design and monitoring activities in the work with families

Purification and Characterisation of a Pore Protein of the Outer Mitochondrial Membrane from Neurospora crassa

The major protein of the outer mitochondrial membrane of Neurospora was purified. On dodecylsulfate-containing gels it displayed a single bend with an apparent molecular weight of 31000. reconstitution experiments with artifical lipid bilayers showed that this protein forms pores. Pore conductance was dependent on the voltage across the membrane. The protein inserted into the membrane in an oriented fashion, the membrane current being dependent on the sign of the voltage. Single pore conductance was 5nS, suggesting a diameter of 2nm of the open pore. This mitochondrial protein shows a number of similarities to the outer membrane porins of gram-negative bacteria