Partitioning 3D space for parallel many-particle stimulations

In a common approach for parallel processing applied to simulations of manyparticle systems with short-ranged interactions and uniform density, the simulation cell is partitioned into domains of equal shape and size, each of which is assigned to one processor. We compare the commonly used simple-cubic (SC) domain shape to domain shapes chosen as the Voronoi cells of BCC and FCC lattices. The latter two are found to result in superior partitionings with respect to communication overhead. Other domain shapes, relevant for a small number of processors, are also discussed. The higher eciency with BCC and FCC partitionings is demonstrated in simulations of the sillium model for amorphous silicon

Shape-induced capilary interactions of colloidal particles

We show that near-spherical micrometer-sized colloidal particles at an interface of two fluids experience inter-particle forces merely as a consequence of their shape-induced capillary interaction. The interaction is strong even if the deviations from sphericity are on the nm-scale, and can hardly be avoided in experiment. For particles of 2 μm radius, a deformation of 20 nm can result in an attractive potential of 2kBT at a distance of 4 particle radii. Dynamical simulations of many particles confirm that the forces lead to aggregates of dendritic or hexagonal-lattice type. The latter pattern exhibits strong herringbone-phase orientational order

Shape-induced capillary interactions of colloidal particles

We show that near-spherical micrometer-sized colloidal particles at an interface of two fluids experience inter-particle forces merely as a consequence of their shape-induced capillary interaction. The interaction is strong even if the deviations from sphericity are on the nm-scale, and can hardly be avoided in experiment. For particles of 2 μm radius, a deformation of 20 nm can result in an attractive potential of 2kBT at a distance of 4 particle radii. Dynamical simulations of many particles confirm that the forces lead to aggregates of dendritic or hexagonal-lattice type. The latter pattern exhibits strong herringbone-phase orientational order

Barriers and facilitators influencing the implementation of the occupational health intervention ‘Dynamic Work’: a qualitative study

© 2022, The Author(s).Background: Sedentary behavior is associated with an increased risk of morbidity and mortality. To reduce occupational sitting time of office workers, the multi-component intervention ‘Dynamic Work’ was implemented in a Dutch insurance company. Although the results showed no significant reductions in sitting time, associations were found between higher levels of implementation and reductions in sitting time. Building upon these findings, this qualitative study aimed to identify barriers and facilitators from an organizational perspective for the implementation of Dynamic Work. In addition, we explored differences in barriers and facilitators between departments with a low, middle and high level of implementation. Methods: In total, eighteen semi-structured interviews were conducted with two Dynamic Work coordinators, three occupational physiotherapists who delivered the intervention, and thirteen department managers. All participants were purposively sampled. The data was coded in Atlas.ti and a thematic analysis was performed guided by The Integrated Checklist of Determinants (TICD). Results: Implementation factors were related to the organization; working culture and financial support facilitated implementation. Factors related to the implementing department mainly hindered implementation, i.e. lack of information at start of the project, late delivery of Dynamic Work equipment, large group sizes, employee’s workload and work tasks, and an ongoing reorganization. The facilitating role of managers was experienced as both enabling and hindering. The pre-existing familiarity of the occupational physiotherapists with the departments and alignment amongst the three implementers facilitated implementation. Yet, the non-obligatory nature of the intervention as well as limited availability and technical problems of equipment did not support implementation. Conclusions: Various barriers and facilitators influenced the implementation of the Dynamic Work intervention, where the key role of the department manager, late delivery of dynamic work equipment and groups sizes varied between low and high implementing departments. These results can contribute to developing and improving implementation strategies in order to increase the effectiveness of future occupational health interventions. Trial registration: The study protocol was registered on April 14, 2017 in the ClinicalTrials.gov Protocol Registration and Results System under registration number NCT03115645

Mixed-methods process evaluation of the Dynamic Work study: A multicomponent intervention for office workers to reduce sitting time

© 2022 The AuthorsPreviously, we observed no significant reductions in sitting time of the multicomponent Dynamic Work (DW) intervention among office workers. In this study we used mixed-method data to understand context, implementation (i.e. recruitment and delivery) and mechanism of impact (i.e. experiences) of the DW intervention and to explore whether an higher implementation index score led to larger changes in participants’ outcomes. We found considerable variation across departments regarding context (i.e. different size and work tasks) and implementation (i.e. delivery varied). Satisfaction with the DW intervention was high. An higher implementation index score was associated with lower overall sitting time, lower occupational sitting time, higher number of steps/day and steps/day at work at 4-months, which was maintained at 8-month for occupational sitting time. These findings provide an understanding that implementation was affected by a lack of availability of intervention components, department policy, work tasks, positioning and work location. Trial registration: Clinicaltrials.gov, registration number:NCT03115645. Registered February 17, 2017 – Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT03115645