New insights into Legionella pneumophila biofilm regulation by c-di-GMP signaling

The waterborne pathogen Legionella pneumophila grows as a biofilm, freely or inside amoebae. Cyclic-di-GMP (c-di-GMP), a bacterial second messenger frequently implicated in biofilm formation, is synthesized and degraded by diguanylate cyclases (DGCs) and phosphodiesterases (PDEs), respectively. To characterize the c-di-GMP-metabolizing enzymes involved in L. pneumophila biofilm regulation, the consequences on biofilm formation and the c-di-GMP concentration of each corresponding gene inactivation were assessed in the Lens strain. The results showed that one DGC and two PDEs enhance different aspects of biofilm formation, while two proteins with dual activity (DGC/PDE) inhibit biofilm growth. Surprisingly, only two mutants exhibited a change in global c-di-GMP concentration. This study highlights that specific c-di-GMP pathways control L. pneumophila biofilm formation, most likely via temporary and/or local modulation of c-di-GMP concentration. Furthermore, Lpl1054 DGC is required to enable the formation a dense biofilm in response to nitric oxide, a signal for biofilm dispersion in many other species

Increasing flower species richness in agricultural landscapes alters insect pollinator networks: Implications for bee health and competition

Ecological restoration programs are established to reverse land degradation, mitigate biodiversity loss, and reinstate ecosystem services. Following recent agricultural intensification that led to a decrease in flower diversity and density in rural areas and subsequently to the decline of many insects, conservation measures targeted at pollinators have been established, including sown wildflower strips (WFS) along field margins. Historically successful in establishing a high density of generalist bees and increasing pollinator diversity, the impact of enhanced flower provision on wider ecological interactions and the structure of pollinator networks has been rarely investigated. Here, we tested the effects of increasing flower species richness and flower density in agricultural landscapes on bee‐plant interaction networks. We measured plant species richness and flower density and surveyed honeybee and bumblebee visits on flowers across a range of field margins on 10 UK farms that applied different pollinator conservation measures. We found that both flower species richness and flower density significantly increased bee abundance, in early and late summer, respectively. At the network level, we found that higher flower species richness did not significantly alter bee species' generality indices, but significantly reduced network connectance and marginally reduced niche overlap across honeybees and bumblebee species, a proxy for insect competition. While higher connectance and niche overlap is believed to strengthen network robustness and often is the aim for the restoration of pollinator networks, we argue that carefully designed WFS may benefit bees by partitioning their foraging niche, limiting competition for resources and the potential for disease transmission via shared floral use. We also discuss the need to extend WFS and their positive effects into spring when wild bee populations are established

Running out of time(rs): effects of scarcity cues on perceived task load, perceived benevolence and user experience on e-commerce sites

peer reviewe

"Do we need an entire course about it?": Evaluating two years of teaching HCI in computer science

Educators increasingly agree on the importance of teaching Human-Computer Interaction (HCI) to Computer Science (CS) students, but there is debate on how to best integrate HCI into CS curricula. Unfortunately, standard course evaluations typically do not provide sufficient insights for improving HCI classes. In the present article, we used a human-centered design approach to evaluate our HCI classes, building on a qualitative study with CS students from four introductory HCI classes over two years. We report on a qualitative assessment through interviews, photo elicitation and sentence completion. Specifically, we addressed four research questions: which contents were the most relevant, how students experienced the courses, how they view the role of HCI in CS, and which outcomes they perceived from the HCI courses. We gathered rich qualitative insights beyond the standard course evaluations and derived concrete enhancements for future course iterations. We discuss implications for other HCI educators and contribute recommendations for the living HCI curriculum. Furthermore, we reflect on the usefulness of our methodological approach to collect in-depth constructive feedback from students

Increasing flower species richness in agricultural landscapes alters insect pollinator networks: implications for bee health and competition

Ecological restoration programs are established to reverse land degradation, mitigate biodiversity loss, and reinstate ecosystem services. Following recent agricultural intensification that led to a decrease in flower diversity and density in rural areas and subsequently to the decline of many insects, conservation measures targeted at pollinators have been established, including sown wildflower strips (WFS) along field margins. Historically successful in establishing a high density of generalist bees and increasing pollinator diversity, the impact of enhanced flower provision on wider ecological interactions and the structure of pollinator networks has been rarely investigated. Here, we tested the effects of increasing flower species richness and flower density in agricultural landscapes on bee-plant interaction networks. We measured plant species richness and flower density and surveyed honeybee and bumblebee visits on flowers across a range of field margins on 10 UK farms that applied different pollinator conservation measures. We found that both flower species richness and flower density significantly increased bee abundance, in early and late summer, respectively. At the network level, we found that higher flower species richness did not significantly alter bee species' generality indices, but significantly reduced network connectance and marginally reduced niche overlap across honeybees and bumblebee species, a proxy for insect competition. While higher connectance and niche overlap is believed to strengthen network robustness and often is the aim for the restoration of pollinator networks, we argue that carefully designed WFS may benefit bees by partitioning their foraging niche, limiting competition for resources and the potential for disease transmission via shared floral use. We also discuss the need to extend WFS and their positive effects into spring when wild bee populations are established

Conservation measures or hotspots of disease transmission? Agri-environment schemes can reduce disease prevalence in pollinator communities

Insects are under pressure from agricultural intensification. To protect pollinators, conservation measures such as the EU agri-environment schemes (AES) promote planting wildflowers along fields. However, this can potentially alter disease ecology by serving as transmission hubs or by diluting infections. We tested this by measuring plant–pollinator interactions and virus infections (DWV-A, DWV-B and ABPV) across pollinator communities in agricultural landscapes over a year. AES had a direct effect on DWV-B, reducing prevalence and load in honeybees, with a tentative general dilution effect on load in early summer. DWV-A prevalence was reduced both under AES and with increasing niche overlap between competent hosts, likely via a dilution effect. By contrast, AES had no impact on ABPV, its prevalence driven by the proportion of bumblebees in the community. Epidemiological differences were also reflected in the virus phylogenies, with DWV-B showing recent rapid expansion, while DWV-A and ABPV showed slower growth rates and geographical population structure. Phylogenies indicate that all three viruses freely circulate across their host populations. Our study illustrates how complex interactions between environmental, ecological and evolutionary factors may influence wildlife disease dynamics. Supporting pollinator nutrition can mitigate the transmission of important bee diseases, providing an unexpected boost to pollinator conservation

Når to kommuner blir til en. En studie av sammenslåingen av den administrative organiseringen til Tjøme og Nøtterøy kommuner

Denne studien har benyttet seg av et casedesign. Studien tar for seg hvordan de to kommunene Tjøme og Nøtterøy danner sin administrative struktur ved en kommunesammenslåing. Studien tar også sikte på å forklare hvorfor kommuneadministrasjonen blir slik. De to kommunene har hatt mye samarbeid på flere velferdsområder og likheter i organisasjonsstruktur. Et organisasjonsperspektiv benyttes for å kartlegge prosessen mot sammenslåingen langs elementene organisasjonsdemografi, -struktur og -sted. Det benyttes kvalitative intervjuer for å samle inn datagrunnlaget for studien. I analysen benyttes en utfyllende strategi hvor det drøftes med bureau-shaping og et institusjonelt perspektiv. Av studien kommer det frem at Nøtterøy sin struktur har blitt dominerende i den nye kommunene, samtidig er det mye samarbeid mellom de gamle kommunene som her videreføres. Her vitnes det også om flere strategier for bureau-shaping og stiavhengige beslutninger som er med på å utforme organisasjonen