The evolution of social networks through the implementation of evidence-informed decision-making interventions: a longitudinal analysis of three public health units in Canada

Background

We studied the evolution of information-seeking networks over a 2-year period during which an organization-wide intervention was implemented to promote evidence-informed decision-making (EIDM) in three public health units in Ontario, Canada. We tested whether engagement of staff in the intervention and their EIDM behavior were associated with being chosen as information source and how the trend of inter-divisional communications and the dominance of experts evolved over time.

Methods

Local managers at each health unit selected a group of staff to get engage in Knowledge Broker-led workshops and development of evidence summaries to address local public health problems. The staff were invited to answer three online surveys (at baseline and two annual follow-ups) including name generator questions eliciting the list of the staff they would turn to for help integrating research evidence into practice. We used stochastic actor-oriented modeling to study the evolution of networks. We tested the effect of engagement in the intervention, EIDM behavior scores, organizational divisions, and structural dynamics of social networks on the tendency of staff to select information sources, and the change in its trend between year 1 and year 2 of follow-up.

Results

In all the three health units, and especially in the two units with higher levels of engagement in the intervention, the network evolved towards a more centralized structure, with an increasing significance of already central staff. The staff showed greater tendencies to seek information from peers with higher EIDM behavior scores. In the public health unit that had highest engagement and stronger leadership support, the engaged staff became more central. In all public health units, the engaged staff showed an increasing tendency towards forming clusters. The staff in the three public health units showed a tendency towards limiting their connections within their divisions.

Conclusions

The longitudinal analysis provided us with a means to study the microstructural changes in public health units, clues to the sustainability of the implementation. The hierarchical transformation of networks towards experts and formation of clusters among staff who were engaged in the intervention show how implementing organizational interventions to promote EIDM may affect the knowledge flow and distribution in health care communities, which may lead to unanticipated consequences.

     

Molecular determinants of binding between Gly-Leu-Phe-Gly nucleoporins and the nuclear pore complex

The vertebrate nucleoporin Nup98 can be expressed in two distinct forms from differentially spliced mRNAs, either as a 98-kDa protein or as the 195-kDa Nup98/Nup96 polyprotein. Both forms undergo autoproteolytic processing to generate the 90-kDa Nup98 and either an 8-kDa tail or the nucleoporin Nup96. An equivalent cleavage event occurs in one yeast ortholog, Nup145, to produce Nup145N and Nup145C. We previously proposed that Nup145N, and possibly the other orthologs Nup116 and Nup100, might bind to Nup145C as demonstrated for Nup98 and Nup96. Here we have further investigated the interaction of both yeast and vertebrate Gly-Leu-Phe-Gly nucleoporins with the nuclear pore. We find that dynamic Nup98 binding can be recapitulated in vitro and that simultaneous translation and folding as a polyprotein are not required to allow subsequent binding between Nup98 and Nup96. We show that Nup145N and Nup145C do indeed bind to each other, and we have determined the dissociation constants for these interactions in vitro. Additionally, we characterize two sites of molecular interaction for each binding pair. Of the yeast orthologs, Nup116 binds far less robustly to Nup145C than does Nup145N, and Nup100 binding is barely detectable. Thus, we conclude that Nup116 and Nup100 likely use means of incorporation into the nuclear pore complex that are distinct from those used by Nup145N.     

Sampling multiple life stages significantly increases estimates of marine biodiversity

Biodiversity assessments are critical for setting conservation priorities, understanding ecosystem function and establishing a baseline to monitor change. Surveys of marine biodiversity that rely almost entirely on sampling adult organisms underestimate diversity because they tend to be limited to habitat types and individuals that can be easily surveyed. Many marine animals have planktonic larvae that can be sampled from the water column at shallow depths. This life stage often is overlooked in surveys but can be used to relatively rapidly document diversity, especially for the many species that are rare or live cryptically as adults. Using DNA barcode data from samples of nemertean worms collected in three biogeographical regions—Northeastern Pacific, the Caribbean Sea and Eastern Tropical Pacific—we found that most species were collected as either benthic adults or planktonic larvae but seldom in both stages. Randomization tests show that this deficit of operational taxonomic units collected as both adults and larvae is extremely unlikely if larvae and adults were drawn from the same pool of species. This effect persists even in well-studied faunas. These results suggest that sampling planktonic larvae offers access to a different subset of species and thus significantly increases estimates of biodiversity compared to sampling adults alone. Spanish abstract is available in the electronic supplementary material.     

Antifouling potential of lubricious, micro-engineered, PDMS elastomers against zoospores of the green fouling alga Ulva (Enteromorpha)

The settlement and release of Ulva spores from chemically modified, micro-engineered surface topographies have been investigated using poly(dimethyl siloxane) elastomers (PDMSe) with varying additions of non-network forming poly(dimethyl siloxane) based oils. The topographic features were based on 5 microns wide pillars or ridges separated by 5, 10, or 20 microns wide channels. Pattern depths were 5 or 1.5 microns. Swimming spores showed no marked difference in settlement on smooth surfaces covered with excess PDMS oils. However, incorporation of oils significantly reduced settlement density on many of the surfaces with topographic features, in particular, the 5 microns wide and deep channels. Previous results, confirmed here, demonstrate preferences by the spores to settle in channels and against pillars with spatial dimensions of 5 microns, 10 microns and 20 microns. The combination of lubricity and pillars significantly reduced the number of attached spores compared to the control, smooth, unmodified PDMSe surfaces when exposed to turbulent flow in a flow channel. The results are discussed in relation to the energy needs for spores to adhere to various surface features and the concepts of ultrahydrophobic surfaces. A factorial, multi-level experimental design was analyzed and a 2nd order polynomial model was regressed for statistically significant effects and interactions to determine the magnitude and direction of influence on the spore density measurements between factor levels.     

Linkage disequilibrium and sequence diversity in a 500-kbp region around the adh1 locus in elite maize germplasm

Linkage disequilibrium (LD) at the adh1 locus was examined in two sets of maize inbreds. A set of 32 was chosen to represent most of the genetic diversity in the cultivated North American elite maize breeding pool. A second set of 192 inbreds was chosen to sample more deeply the two major heterotic groups in elite maize germplasm. Analysis of several loci in the vicinity of the adh1 gene shows that LD as measured by D and r² extends greater than 500 kbp in this germplasm. The presence of this exceptionally long segment of high LD may be suggestive of selection acting on one of the genes in the vicinity of adh1 or of a locally reduced rate of recombination.Electronic Supplementary Material Supplementary material is available for this article at .     

Effects of food processing on masticatory strain and craniofacial growth in a retrognathic face

Changes in the technology of food preparation over the last few thousand years (especially cooking, softening, and grinding) are hypothesized to have contributed to smaller facial size in humans because of less growth in response to strains generated by chewing softer, more processed food. While there is considerable comparative evidence to support this idea, most experimental tests of this hypothesis have been on non-human primates or other very prognathic mammals (rodents, swine) raised on hard versus very soft (nearly liquid) diets. Here, we examine facial growth and in vivo strains generated in response to raw/dried foods versus cooked foods in a retrognathic mammal, the rock hyrax (Procavia capensis). The results indicate that the hyrax cranium resembles the non-human primate cranium in having a steep gradient of strains from the occlusal to orbital regions, but differs from most non-anthropoids in being primarily twisted; the hyrax mandible is bent both vertically and laterally. In general, higher strains, as much as two-fold at some sites, are generated by masticating raw versus cooked food. Hyraxes raised on cooked food had significantly less growth (approximately 10%) in the ventral (inferior) and posterior portions of the face, where strains are highest, resembling many of the differences evident between humans raised on highly processed versus less processed diets. The results support the hypothesis that food processing techniques have led to decreased facial growth in the mandibular and maxillary arches in recent human populations.