Age before beauty? Relationships between fertilization success and age-dependent ornaments in barn swallows

When males become more ornamented and reproduce more successfully as they grow older, phenotypic correlations between ornament exaggeration and reproductive success can be confounded with age effects in cross-sectional studies, and thus say relatively little about sexual selection on these traits. This is exemplified here in a correlative study of male fertilization success in a large colony of American barn swallows (Hirundo rustica erythrogaster). Previous studies of this species have indicated that two sexually dimorphic traits, tail length and ventral plumage coloration, are positively correlated with male fertilization success, and a mechanism of sexual selection by female choice has been invoked. However, these studies did not control for potential age-related variation in trait expression. Here, we show that male fertilization success was positively correlated with male tail length but not with plumage coloration. We also show that 1-year-old males had shorter tails and lower fertilization success than older males. This age effect accounted for much of the covariance between tail length and fertilization success. Still, there was a positive relationship between tail length and fertilization success among older males. But as this group consisted of males from different age classes, an age effect may be hidden in this relationship as well. Our data also revealed a longitudinal increase in both tail length and fertilization success for individual males. We argue that age-dependent ornament expression and reproductive performance in males complicate inferences about female preferences and sexual selection

Guanylate cyclase C activation shapes the intestinal microbiota in patients with familial diarrhea and increased susceptibility for Crohn's Disease

Background: With 25% prevalence of Crohn's disease, Familial GUCY2C diarrhea syndrome (FGDS) is a monogenic disorder potentially suited to study initiating factors in inflammatory bowel disease (IBD). We aimed to characterize the impact of an activating GUCY2C mutation on the gut microbiota in patients with FGDS controlling for Crohn's disease status and to determine whether changes share features with those observed in unrelated patients with IBD. Methods: Bacterial DNA from fecal samples collected from patients with FGDS (N = 20), healthy relatives (N = 11), unrelated healthy individuals (N = 263), and IBD controls (N = 46) was subjected to sequencing of the V3-V4 region of the 16S rRNA gene to determine gut microbiota composition. Food frequency questionnaires were obtained from patients with FGDS and their relatives. Results: Compared with healthy controls, FGDS displayed prominent changes in many microbial lineages including increase in Enterobacteriaceae, loss of Bifidobacterium and Faecalibacterium prausnitzii but an unchanged intraindividual (alpha) diversity. The depletion of F. prausnitzii is in line with what is typically observed in Crohn's disease. There was no significant difference in the dietary profile between the patients and related controls. The gut microbiota in related and unrelated healthy controls was also similar, suggesting that diet and familial factors do not explain the gut microbiota alterations in FGDS. Conclusions: The findings support that the activating mutation in GUCY2C creates an intestinal environment with a major influence on the microbiota, which could contribute to the increased susceptibility to IBD in patients with FGDS

Reading Multiple Documents on Tablet: Effects of Applications and Strategic Guidance on Performance and Acceptance

International audienc

The Orchestration of a Collaborative Information Seeking Learning Task

The paper describes our novel perspective on ‘searching to learn’ through collaborative information seeking (CIS). We describe this perspective, which motivated empirical work to ‘orchestrate’ a CIS searching to learn session. The work is described through the lens of orchestration, an approach which brings to the fore the ways in which: background context – including practical classroom constraints, and theoretical perspective; actors – including the educators, researchers, and technologies; and activities that are to be completed, are brought into alignment. The orchestration is exemplified through the description of research work designed to explore a pedagogically salient construct (epistemic cognition), in a particular institutional setting. Evaluation of the session indicated satisfaction with the orchestration from students, with written feedback indicating reflection from them on features of the orchestration. We foreground this approach to demonstrate the potential of orchestration as a design approach for researching and implementing CIS as a ‘searching to learn’ context