An approach for particle sinking velocity measurements in the 3–400 μm size range and considerations on the effect of temperature on sinking rates

The flux of organic particles below the mixed layer is one major pathway of carbon from the surface into the deep ocean. The magnitude of this export flux depends on two major processes—remineralization rates and sinking velocities. Here, we present an efficient method to measure sinking velocities of particles in the size range from approximately 3–400 μm by means of video microscopy (FlowCAM®). The method allows rapid measurement and automated analysis of mixed samples and was tested with polystyrene beads, different phytoplankton species, and sediment trap material. Sinking velocities of polystyrene beads were close to theoretical values calculated from Stokes’ Law. Sinking velocities of the investigated phytoplankton species were in reasonable agreement with published literature values and sinking velocities of material collected in sediment trap increased with particle size. Temperature had a strong effect on sinking velocities due to its influence on seawater viscosity and density. An increase in 9 °C led to a measured increase in sinking velocities of ~40 %. According to this temperature effect, an average temperature increase in 2 °C as projected for the sea surface by the end of this century could increase sinking velocities by about 6 % which might have feedbacks on carbon export into the deep ocean

Sparsity Data Reduction In Textual Network Analysis. An exercise on Sustainability meaning

In this paper, we propose a new strategy to derive an unweighted adjacency matrix from an affiliation matrix. The strategy is based on the use of a biclustering technique in order to reduce the sparsity of the matrix without changing the network structure. As an example, we implemented this approach to seek the common meaning of the term sustainability by using an affiliation matrix characterized by a core-periphery structure. The application of BiMax Biclustering algorithm shows a sparsity reduction of the unweighted adjacency matrix with an invariant network structure

The transformation competence perspective

Reflections on a number of participative projects have led to the conclusion that, when planning and conducting OR interventions, particular attention should be paid to the transformation to be attempted and to the competence of those who will be involved. The transformation required by a consulting project sets the scope of the ambition that is to be met by the craft skills and expertise of people, supported if appropriate by pre-defined methods. Competence refers to the skills, time and the ability to act of those involved in the intervention. In designing an intervention, activities have to be planned in the light of the transformation required, the competences of those involved and the pre-defined methods available. Pre-defined methods are characterized in terms of their transformation potential, the transformation that can be achieved by using the method in a specific context. The paper elaborates the proposed transformation competence perspective drawing on personal practical experience; its aim is to articulate an approach to the design of participative consulting interventions and compare it with alternatives

Robotic Thyroidectomy for Cancer in the US: Patterns of Use and Short-Term Outcomes

BACKGROUND: We describe nationally representative patterns of utilization and short-term outcomes from robotic versus open thyroidectomy for thyroid cancer. METHODS: Descriptive statistics and multivariable analysis were used to analyze patterns of use of robotic thyroidectomy from the National Cancer Database (2010–2011). Short-term outcomes were compared between patients undergoing robotic versus open thyroidectomy, while adjusting for confounders. RESULTS: A total of 68,393 patients with thyroid cancer underwent thyroidectomy; 225 had robotic surgery and 57,729 underwent open surgery. Robotic thyroid surgery use increased by 30 % from 2010 to 2011 (p = 0.08). Robotic cases were reported from 93 centers, with 89 centers performing <10 robotic cases. Compared with the open group, the robotic group was younger (51 vs. 47 years; p < 0.01) and included more Asian patients (4 vs. 8 %; p = 0.006) and privately-insured patients (68 vs. 77 %; p = 0.01). Tumor size was similar between patients undergoing robotic versus open surgery. Total thyroidectomy was performed less frequently in the robotic group (67 vs. 84 % open; p < 0.0001). Patients were relatively more likely to undergo robotic surgery if they were female (odds ratio [OR] 1.6; p = 0.04), younger (OR 0.8/10 years; p < 0.0001), or underwent lobectomy (OR 2.4; p < 0.0001). In adjusted multivariable analysis, there were no differences in the number of lymph nodes removed or length of stay between groups; however, there was a non-significant increase in the incidence of positive margins with robotic thyroidectomy. CONCLUSIONS: Use of robotic thyroidectomy for thyroid cancer is limited to a few institutions, with short-term outcomes that are comparable to open surgery. Multi-institutional studies should be undertaken to compare thyroidectomy-specific complications and long-term outcomes