The effect of hedgerow age on vegetative species diversity

Hedgerows are a distinctive part of the English countryside and provide many ecological benefits and services. Over recent history, hedgerows have been removed and replanted, resulting in a matrix of different aged hedgerows across the country. In this study, the effect of hedgerow age on vegetative species diversity was tested to see if older hedgerows contained a higher species diversity than younger hedgerows. Four hedgerows of varying ages were tested on an urban farm in Plymouth, Southwest England. Percentage cover of each species was measured across ten samples in each hedgerow, with a Shannon’s diversity score being calculated for each sample and then repeated for each of the four different aged hedgerows. Vegetative species diversity was found to differ between each of the four hedgerows with the Devon bank having the highest diversity score and the orchard hedgerow the lowest. Although some significant differences were found, these were not able to conclude that older hedgerows contain a significantly higher diversity than younger hedgerows. Differences in hedgerow functional group composition were also observed and these may be due to factors other than age such as surrounding land use or structure. Furthermore, the distribution of autumn and winter fruiting species was tested due to their ecological importance and was found that a higher proportion was contained within the old hedgerow. It could be implied that the lack of management on the hedgerows sampled was negatively affecting their diversity through all ages. Future studies would be required to see if the age of hedgerows is influencing diversity and composition by testing a wider range of hedgerow ages and by sampling during different seasons. Recommendations for future hedgerow management have been made based on the surrounding literature in order to improve hedgerow diversity and its subsequent benefits

An open-source framework for synthetic post-dive Doppler ultrasound audio generation

Doppler ultrasound (DU) measurements are used to detect and evaluate venous gas emboli (VGE) formed after decompression. Automated methodologies for assessing VGE presence using signal processing have been developed on varying real-world datasets of limited size and without ground truth values preventing objective evaluation. We develop and report a method to generate synthetic post-dive data using DU signals collected in both precordium and subclavian vein with varying degrees of bubbling matching field-standard grading metrics. This method is adaptable, modifiable, and reproducible, allowing for researchers to tune the produced dataset for their desired purpose. We provide the baseline Doppler recordings and code required to generate synthetic data for researchers to reproduce our work and improve upon it. We also provide a set of pre-made synthetic post-dive DU data spanning six scenarios representing the Spencer and Kisman-Masurel (KM) grading scales as well as precordial and subclavian DU recordings. By providing a method for synthetic post-dive DU data generation, we aim to improve and accelerate the development of signal processing techniques for VGE analysis in Doppler ultrasound

tartan underlies the evolution of male Drosophila genital morphology

Male genital structures are among the most rapidly evolving morphological traits and are often the only features that can distinguish closely related species. This process is thought to be driven by sexual selection and may reinforce species separation. However, while the genetic bases of many phenotypic differences have been identified, we still lack knowledge about the genes underlying evolutionary differences in male genital organs and organ size more generally. The claspers (surstyli) are periphallic structures that play an important role in copulation in insects. Here, we show that divergence in clasper size and bristle number between Drosophila mauritiana and Drosophila simulans is caused by evolutionary changes in tartan (trn), which encodes a transmembrane leucine-rich repeat domain protein that mediates cell–cell interactions and affinity. There are no fixed amino acid differences in trn between D. mauritiana and D. simulans, but differences in the expression of this gene in developing genitalia suggest that cis-regulatory changes in trn underlie the evolution of clasper morphology in these species. Finally, analyses of reciprocal hemizygotes that are genetically identical, except for the species from which the functional allele of trn originates, determined that the trn allele of D. mauritiana specifies larger claspers with more bristles than the allele of D. simulans. Therefore, we have identified a gene underlying evolutionary change in the size of a male genital organ, which will help to better understand not only the rapid diversification of these structures, but also the regulation and evolution of organ size more broadly