Global fine-resolution data on springtail abundance and community structure.

Springtails (Collembola) inhabit soils from the Arctic to the Antarctic and comprise an estimated ~32% of all terrestrial arthropods on Earth. Here, we present a global, spatially-explicit database on springtail communities that includes 249,912 occurrences from 44,999 samples and 2,990 sites. These data are mainly raw sample-level records at the species level collected predominantly from private archives of the authors that were quality-controlled and taxonomically-standardised. Despite covering all continents, most of the sample-level data come from the European continent (82.5% of all samples) and represent four habitats: woodlands (57.4%), grasslands (14.0%), agrosystems (13.7%) and scrublands (9.0%). We included sampling by soil layers, and across seasons and years, representing temporal and spatial within-site variation in springtail communities. We also provided data use and sharing guidelines and R code to facilitate the use of the database by other researchers. This data paper describes a static version of the database at the publication date, but the database will be further expanded to include underrepresented regions and linked with trait data.

Checklist of the springtails (Hexapoda: Collembola) of the Edough massif, northeastern Algeria.

Based on 225 samples taken from different biotopes in the Edough Massif (northeastern Algeria) from 1998 to 2018, we compiled a list of 91 collembolan species names from the literature, of which 72 can be considered valid records. Fourteen of them are only known from this massif in Algeria, and eight are endemic of northeastern Algeria. These 72 species are spread over 14 families and 49 genera. The family Neanuridae is the most diverse with 18 species, including six species of the genus Friesea. The monotypic genus Edoughnura (Neanurinae) is endemic to the Edough and Collo massifs. Several of the listed species do not fully match the diagnosis of the species to which they have been assigned and may represent undescribed taxa. Entomobryidae as well as several habitats (epigean, deep soil, littoral) remain unsampled or undersampled in Edough, and are likely to host many more species than those listed in this paper.

Stress influence on orthodontic system components under simulated treatment loadings.

BACKGROUND AND OBJECTIVE: Mini-implants have been developed and effectively used by clinicians as anchorage for orthodontic tooth movement. The objective of this study was to elucidate the stress response of orthodontic forces on the periodontal system, bone tissues, mini-implant and the bracket-enamel interface. METHODS: Computer tomography images of a commercially available mini-implant, an orthodontic bracket bonded to a central incisor, and jawbone section models were used to reconstruct three dimensional computer models. These models were exported and meshed in an ABAQUSⓇ finite-element package. Material properties, multi-segment interactions, boundary and loading conditions were then applied to each component. Finite-element analyses were conducted to elucidate the effect of orthodontic force on the equivalent von Mises stress response within the simulated orthodontic system. RESULTS: The highest stress values in the orthodontic system were predicted at the mini-implant neck, at the interface of the cortical bone, and gradually decreased in the internal apical direction of the miniscrew. On the alveolar bone, the maximum stress values were located in the alveolar cortical bone near the cervical areas of the mini-implant, which is in line with clinical findings of area where bone loss was found post orthodontic tooth treatment. Another peak of von Mises stress response was found in the enamel bracket junction with a maximum up to 186.05 MPa. To ensure good bonding between the enamel and bracket, it is vital to select carefully the type and amount of bonding materials used in the bracket-enamel interface to assure an appropriate load distribution between the teeth and alveolar bone. The results also revealed the significance of the periodontal ligaments, acting as an intermediate cushion element, in the load transfer mechanism. CONCLUSIONS: This study is sought to identify the stress response in a simulated orthodontic system to minimize the failure rate of mini-implants and bracket loss during orthodontic treatment.