Groovy and gnarly : surface wrinkles as a multifunctional motif for terrestrial and marine environments

From large ventral pleats of humpback whales to nanoscale ridges on flower petals, wrinkled structures are omnipresent, multifunctional, and found at hugely diverse scales. Depending on the particulars of the biological system—its environment, morphology, and mechanical properties—wrinkles may control adhesion, friction, wetting, or drag; promote interfacial exchange; act as flow channels; or contribute to stretching, mechanical integrity, or structural color. Undulations on natural surfaces primarily arise from stress-induced instabilities of surface layers (e.g., buckling) during growth or aging. Variation in the material properties of surface layers and in the magnitude and orientation of intrinsic stresses during growth lead to a variety of wrinkling morphologies and patterns which, in turn, reflect the wide range of biophysical challenges wrinkled surfaces can solve. Therefore, investigating how surface wrinkles vary and are implemented across biological systems is key to understanding their structure-function relationships. In this work, we synthesize the literature in a metadata analysis of surface wrinkling in various terrestrial and marine organisms to review important morphological parameters and classify functional aspects of surface wrinkles in relation to the size and ecology of organisms. Building on our previous and current experimental studies, we explore case studies on nano/micro-scale wrinkles in biofilms, plant surfaces, and basking shark filter structures to compare developmental and structure-vs-function aspects of wrinkles with vastly different size scales and environmental demands. In doing this and by contrasting wrinkle development in soft and hard biological systems, we provide a template of structure-function relationships of biological surface wrinkles and an outlook for functionalized wrinkled biomimetic surfaces

Probing inner and outer disk misalignments in transition disks: constraints from VLTI/GRAVITY and ALMA observations

Stars and planetary system

Probing inner and outer disk misalignments in transition disks

This is the final version. Available from EDP Sciences via the DOI in this record. All codes used for the data analysis, as well as example data files, are available at https://github.com/18alex96/disk_misalignmentsContext. Transition disks are protoplanetary disks with dust-depleted cavities, possibly indicating substantial clearing of their dust content by a massive companion. For several known transition disks, dark regions interpreted as shadows have been observed in scattered light imaging and are hypothesized to originate from misalignments between distinct regions of the disk. Aims. We aim to investigate the presence of misalignments in transition disks. We study the inner disk (10 au). Methods. We fit simple parametric models to the visibilities and closure phases of the GRAVITY data to derive the inclination and position angle of the inner disks. The outer disk geometries were derived from Keplerian fits to the ALMA velocity maps and compared to the inner disk constraints. We also predicted the locations of expected shadows for significantly misaligned systems. Results. Our analysis reveals six disks to exhibit significant misalignments between their inner and outer disk structures. The predicted shadow positions agree well with the scattered light images of HD 100453 and HD 142527, and we find supporting evidence for a shadow in the south of the disk around CQ Tau. In the other three targets for which we infer significantly misaligned disks, V1247 Ori, V1366 Ori, and RY Lup, we do not see any evident sign of shadows in the scattered light images. The scattered light shadows observed in DoAr 44, HD 135344 B, and HD 139614 are consistent with our observations, yet the underlying morphology is likely too complex to be described properly by our models and the accuracy achieved by our observations. Conclusions. The combination of near infrared and submillimeter interferometric observations allows us to assess the geometries of the innermost disk regions and those of the outer disk. Whereas we can derive precise constraints on the potential shadow positions for well-resolved inner disks around Herbig Ae/Be stars, the large statistical uncertainties for the marginally resolved inner disks around the T Tauri stars of our sample make it difficult to extract conclusive constraints for the presence of shadows in these systems.European Research CouncilEuropean Research CouncilEuropean Research CouncilEuropean Research CouncilEuropean Research CouncilDeutsche Forschungsgemeinschaft (DFG, German Research Foundation)Science Foundation Irelan

Effects of scaling and locomotor ecology suggest a complex evolution of scapular morphology in sciuromorph rodents

Sciuromorph rodents are a monophyletic group comprising ~300 species that display a variety of locomotor behaviours and a body mass range spanning three orders of magnitude. We asked how the interaction of body mass and locomotor ecology affects the morphology of the scapula. Univariate traits and the shape of the scapula from the lateral view of 186 species were analysed. Fitting Ornstein–Uhlenbeck models to all univariate traits revealed phylogenetic inertia to be low. Hence, ordinary least squares regressions including an interaction term were used for all traits to test whether the scaling relationships differ in the fossorial and aerial groups when compared with the group characterized by arboreal locomotion, the most probable ancestral sciuromorph condition. We also asked whether the scaling of univariate traits departs from isometry in each of the three locomotor groups. The aerial group was expected to show the highest trait values for a given body mass and the highest slope values, followed by the arboreal and fossorial groups along this sequence. Only a few traits showed a difference in scaling among locomotor groups and/or a distinct allometric pattern. Discrepancies between our expectations and results are discussed in a morphofunctional context

Embeddedness and empathy: How the social network shapes adolescents' social understanding

Based on theories of social-cognitive development, the present study investigated the yet unknown social structure that underlies the concept of empathy in adolescence. A total of 3.159 seventh graders (13.67 years, 56% girls) from 166 school classes participated by providing information on empathy, related psychosocial factors, and friendship patterns. Social network analyses were used to measure a comprehensive representation of adolescents’ social environment by covering individual, group, class, and school characteristics. Multilevel models revealed that individual characteristics as well as contextual factors predict adolescents’ level of empathy. Findings indicate that empathy is mirrored in the social structure of adolescents supporting the hypothesis that social demands, which continuously grow with the amount of embeddedness, shape their social understanding

Embeddedness and empathy: how the social network shapes adolescents' social understanding.

Based on theories of social-cognitive development, the present study investigated the yet unknown social structure that underlies the concept of empathy in adolescence. A total of 3.159 seventh graders (13.67 years, 56% girls) from 166 school classes participated by providing information on empathy, related psychosocial factors, and friendship patterns. Social network analyses were used to measure a comprehensive representation of adolescents’ social environment by covering individual, group, class, and school characteristics. Multilevel models revealed that individual characteristics as well as contextual factors predict adolescents’ level of empathy. Findings indicate that empathy is mirrored in the social structure of adolescents supporting the hypothesis that social demands, which continuously grow with the amount of embeddedness, shape their social understanding

Integrating Northern Ireland: Cross‐group friendships in integrated and mixed schools

While Northern Ireland strives to build a shared society, the current reality is that everyday experiences are still shaped by division along ethno‐religious lines. This is particularly pronounced in the education system, where more than 92% of pupils attend separate schools. Within the predominantly separate education system, however, exists a small collection of schools which cater to a more heterogeneous pupil body and offer the opportunity for young people from both communities to meet and interact, and potentially develop cross‐group friendships. The present study compares the network‐based cross‐group friendships within two such school types; an integrated and a separate post‐primary school. These schools boast a distinct ethos yet they similarly enrol students from Catholic and Protestant backgrounds. Findings reveal that both schools show a high level of interconnection between pupils; however, the integrated school, with an ethos that openly supports social cohesion, shows a greater tendency towards cross‐group interactions and best friendships than those found within the separate school. In line with contact theory, these findings suggest that it may not be enough to simply create opportunities for intergroup contact but that optimal conditions, such as institutional support, may be a prerequisite for positive relationships to flourish. Implications for educational policies designed to promote greater cross‐community contact are discussed