The effect of different playing surfaces on soccer skill performance

Football (soccer) is traditionally played on natural grass but artificial surfaces are becoming an increasing popular alternative. Understanding how different surfaces affect a player's skill performance has not been examined. This study sought to compare soccer skill performance, using a validated test, on natural grass, third generation (3G) artificial turf, and indoor sprung wooden floor. Following familiarisation, 14 male players (12.7 ± 0.5 years-old, with 6.21 years playing experience) performed the Loughborough Soccer Passing Test (LSPT) on three different surfaces in the following order: indoor, grass and artificial turf. Players were given two practise attempts before the best of two trials were recorded. Movement time was faster on artificial turf (45.1 ± 1.3 s) than natural grass (46.2 ± 1.8 s; p = 0.045), but there was no difference in overall LSPT performance between grass (54.1 ± 4.2 s) and artificial turf (54.0 ± 4.7 s; p = 0.92). Overall LSPT performance was better on indoor surface (50.9 ± 4.6 s) than grass (p = 0.02) and artificial turf (p = 0.02) due to reduced penalty time on the indoor surface (5.5 ± 3.3 s) than grass (7.9 ± 2.9 s; p = 0.001) and artificial turf (8.9 ± 3.9 s; p = 0.003). There is no difference in soccer skill performance between grass and 3G artificial turf. Skill performance on an indoor surface was ∼6% better than both grass and 3G artificial turf due to better ball control and/or accuracy of passing. Our findings will enable comparison of studies using the LSPT on indoor and outdoor (grass or artificial) surfaces.

Ambient Climate Influences Anti-Adhesion between Biomimetic Structured Foil and Nanofibers

Due to their uniquely high surface-to-volume ratio, nanofibers are a desired material for various technical applications. However, this surface-to-volume ratio also makes processing difficult as van der Waals forces cause nanofibers to adhere to virtually any surface. The cribellate spider Uloborus plumipes represents a biomimetic paragon for this problem: these spiders integrate thousands of nanofibers into their adhesive capture threads. A comb on their hindmost legs, termed calamistrum, enables the spiders to process the nanofibers without adhering to them. This anti-adhesion is due to a rippled nanotopography on the calamistrum. Via laser-induced periodic surface structures (LIPSS), these nanostructures can be recreated on artificial surfaces, mimicking the non-stickiness of the calamistrum. In order to advance the technical implementation of these biomimetic structured foils, we investigated how climatic conditions influence the anti-adhesive performance of our surfaces. Although anti-adhesion worked well at low and high humidity, technical implementations should nevertheless be air-conditioned to regulate temperature: we observed no pronounced anti-adhesive effect at temperatures above 30 °C. This alteration between anti-adhesion and adhesion could be deployed as a temperature-sensitive switch, allowing to swap between sticking and not sticking to nanofibers. This would make handling even easier.

Artificial Surfaces and Media for Electromagnetic Absorption and Interference Shielding

The rapid advent of radio-frequency (RF) and microwave technologies and systems have given rise to serious electromagnetic pollution, interference and jamming for high-precision detection devices, and even threats to human health. To mitigate these negative impacts, electromagnetic interference (EMI) shielding materials and structures have been widely deployed to isolate sophisticated instruments or human settlements from potential EMI sources growing every day. We discuss recent advances in lightweight, low-profile electromagnetic absorbing media, such as metamaterials, metasurfaces, and nanomaterial-based solutions, which may provide a relatively easy solution for EMI shielding and suppressing unwanted RF and microwave noises. We present a general review of the recent progress on theories, designs, modeling techniques, fabrication, and performance comparison for these emerging EMI and electromagnetic compatibility (EMC) media.

Habitat use by post-fledging white-tailed eagles shows avoidance of human infrastructure and agricultural areas

Habitat use studies provide invaluable information for the conservation of species that suffer from habitat loss or degradation. We used satellite telemetry to study the habitat use of white-tailed eagles (Haliaeetus albicilla) in relation to six habitat classes (artificial surfaces, agricultural areas, forests, semi-natural areas, wetlands and waterbodies) and five forest age classes (0–9, 10–19, 20–59, 60–99 and ≥ 100 years old) during the post-fledging period in Finland. The post-fledging period, defined here as the period between fledging and dispersal from the natal area, is a critical life-history stage. Our primary objective was to provide information that could be integrated into landscape planning, including wind-energy development (which poses a threat to white-tailed eagles). We found that the habitat classes that were selected by the young white-tailed eagles were forests, semi-natural areas (i.e., transitional woodland and bare rock) and wetlands. When using forests, the eagles selected stands of 0–9 years old, presumably due to the use of retention trees surrounded by a clear-cut as perching sites. Conversely, the habitat classes that were avoided were artificial surfaces, agricultural areas and (the immediate vicinity of) waterbodies. We conclude that the conversion of natural habitats into built and agricultural areas is detrimental to young white-tailed eagles because it reduces habitat availability. They, however, appear to be capable of using forests recently impacted by forestry if perch trees are present. Careful landscape planning is needed to protect priority habitats and avoid conflicts with an expanding white-tailed eagle population (e.g., by building wind farms in areas already environmentally disturbed).

Using metabarcoding and « Diat.Barcode » database to perfom molecular identification on marine biofilms

Marine benthic diatoms highly contribute to biofilms formation, playing a crucial role on both living and artificial surfaces ‘colonization (Briand 2017, Salta 2013). However, their microscopic morphological identification is time consuming and requires a high expertise in taxonomy. We therefore decided to look toward molecular analyses and especially metabarcoding. In this study, we determine : (i) if the use of the “Diat.barcode” database, mostly developed for freshwater diatoms (Rimet 2019), is relevant to characterize marine biofilm communities, (ii) if the amplification of degenerated primers targeting the rbcL gene (Vasselon et al. 2017) could improve the diversity of marine diatom biofilms, and (iii) if molecular and morphological analyses could be correlated.A large majority of OTUs (>95%) was affiliated using the “Diat.barcode” database and the pipeline FROGS, with coverage and affinity values above 80%. OTUs tables contained 75% of diatom species already reported from marine environment, with 82% belonging to the pennates group. The use of degenerated primers significantly improved richness and diversity. Moreover, it allowed us to identify taxa that were not present before, as Iconella, Sellaphora and Coronia. Finally, we showed higher richness and diversity, but also a higher repeatability (replicates closeness) leading to a better clustering with metabarcoding. We found differences in terms of biomarkers, but more broadly, we were able to correlate significantly (r = 0,404; p<0.0001) diatom assemblages.While the latest version of “Diat.barcode” database contains only 12.4% species referenced as marine, it appears to be a powerful tool, even on biofilm samples from the Mediterranean, Baltic seas and Indian Ocean. Furthermore, we confirmed the relevance of degenerated primers to amplify a higher diversity of diatoms. Finally, beta-diversity similarity using molecular and microscopic analysis appeared positive, leading to the conclusion that the two methods should be used in a complementary way.

Code Descriptions

The FFS method (see Sect. 10.1007/978-3-030-61909-1_3) was developed to simulate direct shear tests. To provide a tool for the project work and get things easier done a graphical user interface (GUI) was also created. The GUI simply calls all necessary functions by letting the user either fill form fields or choose input files from the working folder. The rock parameters and the conditions of the direct shear test with the normal stress levels and shear displacements have to be selected. If an experiment is simulated the lab results can be selected as a text file so a visual comparison is possible. The geometry has to be loaded as a point cloud or an artificial surface can be generated. With small modifications the code can do multiple executions using artificial surfaces.

T cells exhibit unexpectedly low discriminatory power and can respond to ultra-low affinity peptide-MHC ligands

T cells use their T cell receptors (TCRs) to discriminate between peptide MHC (pMHC) ligands that bind with different affinities but precisely how different remains controversial. This is partly because the affinities of physiologically relevant interactions are often too weak to measure. Here, we introduce a surface plasmon resonance protocol to measure ultra-low TCR/pMHC affinities (KD ~ 1000 μM). Using naïve, memory, and blasted human CD8+ T cells we find that their discrimination power is unexpectedly low, in that they require a large >100-fold decrease in affinity to abolish responses. Interestingly, the discrimination power reduces further when antigen is presented in isolation on artificial surfaces but can be partially restored by adding ligands to CD2 or LFA-1. We were able to fit the kinetic proof-reading model to our data, yielding the first estimates for both the time delay (2.8 s) and number of biochemical steps (2.67). The fractional number of steps suggest that one of the proof-reading steps is not easily reversible.

Urban Sprawl and Growth Prediction for Lagos Using GlobeLand30 Data and Cellular Automata Model

Urban growth in various cities across the world, especially in developing countries, leads to land use change. Thus, predicting future urban growth in the most rapidly growing region of Nigeria becomes a significant endeavor. This study analyzes land use and land cover (LULC) change and predicts the future urban growth of the Lagos metropolitan region, using Cellular Automata (CA) model. To achieve this, the GlobeLand30 datasets from years 2000 and 2010 were used to obtain LULC maps, which were utilized for modeling and prediction. Change analysis and prediction for LULC scenario for 2030 were performed using LCM and CA_Markov chain modeling. The results show a substantial growth of artificial surfaces, which will cause further reductions in cultivated land, grassland, shrubland, wetland, and waterbodies. There was no appreciable impact of change for bare land, as its initial extent of cover later disappeared completely. Additionally, artificial surfaces/urban growth in Lagos expanded to the neighboring towns and localities in Ogun State during the study period, and it is expected that such growth will be higher in 2030. Lastly, the study findings will be beneficial to urban planners and land use managers in making key decisions regarding urban growth and improved land use management in Nigeria.