195 research outputs found

    Sticky Seeding in Discrete-Time Reversible-Threshold Networks

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    When nodes can repeatedly update their behavior (as in agent-based models from computational social science or repeated-game play settings) the problem of optimal network seeding becomes very complex. For a popular spreading-phenomena model of binary-behavior updating based on thresholds of adoption among neighbors, we consider several planning problems in the design of Sticky Interventions: when adoption decisions are reversible, the planner aims to find a Seed Set where temporary intervention leads to long-term behavior change. We prove that completely converting a network at minimum cost is Ω(ln(OP T ))-hard to approximate and that maximizing conversion subject to a budget is (1 − 1 )-hard to approximate. Optimization heuristics which rely on many objective e-function evaluations may still be practical, particularly in relatively-sparse networks: we prove that the long-term impact of a Seed Set can be evaluated in O(|E|2) operations. For a more descriptive model variant in which some neighbors may be more influential than others, we show that under integer edge weights from {0, 1, 2, ..., k} objective function evaluation requires only O(k|E|2) operations. These operation bounds are based on improvements we give for bounds on time-steps-to-convergence under discrete-time reversible-threshold updates in networks

    Balance revisited: towards deeply functioning practices for actors and organisations

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    This essay revisits the concept of balance and seeks to understand balance as a meta-level principle of any management control and performance measurement system. The essay builds a conceptual background for the concept of balance and unveils several perspectives to be taken to achieve balance, i.e., the different perspectives and viewpoints that should be somehow set into purposeful proportions regarding each other. The relevance of revisiting the concept of balance lies in the possibility to form practices that are deeply and sustainably functioning and constructive for different actors, organisations or other entities. This thought is addressed by using a lighthouse metaphor, in this essay

    EFFECT OF POLYMER ADSORPTION ON CELLULOSE NANOFIBRIL WATER BINDING CAPACITY AND AGGREGATION

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    Polymer adsorption on cellulose nanofibrils and the effect on nanofibril water binding capacity were studied using cellulose nanofibril films together with quartz crystal microbalance with dissipation (QCM-D) and surface plasmon resonance (SPR). The experiments were performed in the immersed state, and special attention was paid to the effect of polymer properties on the water content and viscoelastic properties of the polymer/fibril layer. The dry mass of the adsorbed polymers was determined using SPR. The type of the adsorbed polymer strongly affected the water content and viscoelastic properties of the nanofibril film. The adsorption of a highly charged flocculating polymer, PDADMAC, caused dehydration of the film, which was also detected as nanofibril film stiffening. The adsorption of xyloglucan introduced a dispersing effect to the nanofibril film, which was detected as a loosening and softening of the nanofibril/polymer layer. A dispersing effect was also achieved with carboxymethyl cellulose (CMC), but CMC did not adsorb irreversibly on the nanofibril surfaces. In addition to the nanofibril film studies, the effect of polymer adsorption on cellulose nanofibril suspension aggregation was demonstrated using confocal laser scanning microscopy (CLSM). Xyloglucan was shown to open the nanofibril aggregate structures and act as a dispersing agent, whereas the other polymers studied did not have as significant an effect on aggregation

    Long-term improvement of symptoms of angina pectoris after successful revascularization of coronary artery chronic total occlusions

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    Objectives. To compare long-term angina pectoris relief of successful versus failed percutaneous coronary intervention of chronic total occlusions (CTO PCI). Background. Previous studies demonstrate better short-term angina pectoris relief of CTO PCI than with optimal medical treatment (OMT), however, data on the long-term effects are lacking. Methods. 295 patients undergoing CTO PCI were analyzed retrospectively, with a follow-up evaluation of symptoms of angina pectoris and all-cause death one to four years after the intervention. The primary outcome was long-term relief of symptoms of angina pectoris. Secondary outcomes included a composite of major adverse cardiovascular events (MACE), including all-cause death, myocardial infarction, stroke, and later target vessel revascularization (TVR). At follow-up, patients were interviewed for symptoms of angina pectoris at 1, 6, 12, and 22 to 48 months after the intervention. Results. CTO PCI was successful in 225 (76%) patients and failed in 70 (24%) patients. Short-term (six months) relief of angina pectoris was observed in both groups, but only the successful CTO PCI group showed long-term relief. The Kaplan-Meier curves of all-cause death did not differ between the groups (p = .715). The final follow-up was a mean (range) of 37 (25 to 44) months after the intervention in the successful CTO PCI group, and 33 (28 to 48) months in the failed CTO PCI group. Conclusions. Successful CTO PCI is associated with better long-term relief of symptoms of angina pectoris compared to failed CTO PCI.Peer reviewe

    Microbial Communities of Cladonia Lichens and Their Biosynthetic Gene Clusters Potentially Encoding Natural Products

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    Lichens have been widely used in traditional medicine, especially by indigenous communities worldwide. However, their slow growth and difficulties in the isolation of lichen symbionts and associated microbes have hindered the pharmaceutical utilisation of lichen-produced compounds. Advances in high-throughput sequencing techniques now permit detailed investigations of the complex microbial communities formed by fungi, green algae, cyanobacteria, and other bacteria within the lichen thalli. Here, we used amplicon sequencing, shotgun metagenomics, and in silico metabolomics together with compound extractions to study reindeer lichens collected from Southern Finland. Our aim was to evaluate the potential of Cladonia species as sources of novel natural products. We compared the predicted biosynthetic pathways of lichen compounds from isolated genome-sequenced lichen fungi and our environmental samples. Potential biosynthetic genes could then be further used to produce secondary metabolites in more tractable hosts. Furthermore, we detected multiple compounds by metabolite analyses, which revealed connections between the identified biosynthetic gene clusters and their products. Taken together, our results contribute to metagenomic data studies from complex lichen-symbiotic communities and provide valuable new information for use in further biochemical and pharmacological studies

    Microbial Communities of Cladonia Lichens and Their Biosynthetic Gene Clusters Potentially Encoding Natural Products

    Get PDF
    Lichens have been widely used in traditional medicine, especially by indigenous communities worldwide. However, their slow growth and difficulties in the isolation of lichen symbionts and associated microbes have hindered the pharmaceutical utilisation of lichen-produced compounds. Advances in high-throughput sequencing techniques now permit detailed investigations of the complex microbial communities formed by fungi, green algae, cyanobacteria, and other bacteria within the lichen thalli. Here, we used amplicon sequencing, shotgun metagenomics, and in silico metabolomics together with compound extractions to study reindeer lichens collected from Southern Finland. Our aim was to evaluate the potential of Cladonia species as sources of novel natural products. We compared the predicted biosynthetic pathways of lichen compounds from isolated genome-sequenced lichen fungi and our environmental samples. Potential biosynthetic genes could then be further used to produce secondary metabolites in more tractable hosts. Furthermore, we detected multiple compounds by metabolite analyses, which revealed connections between the identified biosynthetic gene clusters and their products. Taken together, our results contribute to metagenomic data studies from complex lichen-symbiotic communities and provide valuable new information for use in further biochemical and pharmacological studies

    Complete genome sequence of Leuconostoc gelidum subsp. gasicomitatum KG16-1, isolated from vacuum-packaged vegetable sausages

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    Leuconostoc gelidum subsp. gasicomitatum is a predominant lactic acid bacterium (LAB) in spoilage microbial communities of different kinds of modified-atmosphere packaged (MAP) food products. So far, only one genome sequence of a poultry-originating type strain of this bacterium (LMG 18811T) has been available. In the current study, we present the completely sequenced and functionally annotated genome of strain KG16-1 isolated from a vegetable-based product. In addition, six other vegetable-associated strains were sequenced to study possible “niche” specificity suggested by recent multilocus sequence typing. The genome of strain KG16-1 consisted of one circular chromosome and three plasmids, which together contained 2,035 CDSs. The chromosome carried at least three prophage regions and one of the plasmids encoded a galactan degradation cluster, which might provide a survival advantage in plant-related environments. The genome comparison with LMG 18811T and six other vegetable strains suggests no major differences between the meat- and vegetable-associated strains that would explain their “niche” specificity. Finally, the comparison with the genomes of other leuconostocs highlights the distribution of functionally interesting genes across the L. gelidum strains and the genus Leuconostoc.Peer reviewe

    Complete genome sequence of Leuconostoc gelidum subsp. gasicomitatum KG16-1, isolated from vacuum-packaged vegetable sausages

    Get PDF
    Leuconostoc gelidum subsp. gasicomitatum is a predominant lactic acid bacterium (LAB) in spoilage microbial communities of different kinds of modified-atmosphere packaged (MAP) food products. So far, only one genome sequence of a poultry-originating type strain of this bacterium (LMG 18811T) has been available. In the current study, we present the completely sequenced and functionally annotated genome of strain KG16-1 isolated from a vegetable-based product. In addition, six other vegetable-associated strains were sequenced to study possible “niche” specificity suggested by recent multilocus sequence typing. The genome of strain KG16-1 consisted of one circular chromosome and three plasmids, which together contained 2,035 CDSs. The chromosome carried at least three prophage regions and one of the plasmids encoded a galactan degradation cluster, which might provide a survival advantage in plant-related environments. The genome comparison with LMG 18811T and six other vegetable strains suggests no major differences between the meat- and vegetable-associated strains that would explain their “niche” specificity. Finally, the comparison with the genomes of other leuconostocs highlights the distribution of functionally interesting genes across the L. gelidum strains and the genus Leuconostoc.Peer reviewe
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