Study design and mark-recapture estimates of dispersal: A case study with the endangered damselfly Coenagrion mercuriale

Accurate data on dispersal ability are vital to the understanding of how species are affected by fragmented landscapes. However, three factors may limit the ability of field studies to detect a representative sample of dispersal events: (1) the number of individuals monitored, (2) the area over which the study is conducted and (3) the time over which the study is conducted. Using sub-sampling of mark-release-recapture data from a study on the endangered damselfly Coenagrion mercuriale (Charpentier), we show that maximum dispersal distance is strongly related to the number of recaptured individuals in the mark-release-recapture study and the length of time over which the study is conducted. Median dispersal distance is only related significantly to the length of the study. Spatial extent is not associated with either dispersal measure in our analysis. Previously consideration has been given to the spatial scale of dispersal experiments but we demonstrated conclusively that temporal scale and the number of marked individuals also have the potential to affect the measurement of dispersal. Based on quadratic relationships between the maximum dispersal distance, recapture number and length of study, we conclude that a previous study was of sufficient scale to characterise the dispersal kernel of C. mercuriale. Our method of analysis could be used to ensure that the results of mark-release-recapture studies are independent of levels of spatial and temporal investment. Improved confidence in dispersal estimates will enable better management decisions to be made for endangered species

The impact of climate-induced distributional changes on the validity of biological water quality metrics

We present data on the distributional changes within an order of macroinvertebrates used in biological water quality monitoring. The British Odonata (dragonflies and damselflies) have been shown to be expanding their range northwards and this could potentially affect the use of water quality metrics. The results show that the families of Odonata that are used in monitoring are shifting their ranges poleward and that species richness is increasing through time at most UK latitudes. These past distributional shifts have had negligible effects on water quality indicators. However, variation in Odonata species richness (particularly in species-poor regions) has a significant effect on water quality metrics. We conclude with a brief review of current and predicted responses of aquatic macroinvertebrates to environmental warming and maintain that caution is warranted in the use of such dynamic biological indicators

Wings of Coenagrion puella vary in shape at the northern range margin (Odonata: Coenagrionidae)

A previous study has shown that wing size in Coenagrion puella varied considerably along a latitudinal gradient in the UK. Using landmark data from wing images, patterns of shape variation were also determined along the same transect by geometric morphometric analysis of wing shape. Wing shape was uniform at all sites other than those closest to the range margin, which differed significantly. The potential mechanisms that might have generated such between-population variation are discussed

Ultrasound guided placement of the distal catheter in paediatric ventriculoatrial shunts—an appraisal of efficacy and complications

Ventriculoatrial (VA) shunts are commonly used as a second-line treatment of hydrocephalus when the peritoneum is an unsuitable site for the distal catheter. Many centres now utilise ultrasound and interventional radiology techniques to aid placement of the distal catheter. The purpose of this study was to conduct a contemporary audit of VA shunting in children using interventional radiology techniques for placement of the distal catheter

Global variation in early epidemic growth rates and reproduction number of seasonal influenza

Background: Little is known about global variation in early epidemic growth rates and effective reproduction numbers (Re) of seasonal influenza. We aimed to estimate global variation in Re of influenza type A and B during a single period. Methods: Country influenza detection time series from September 2017 through January 2019 were obtained from an international database. Type A and B epidemics by country were selected on the basis of Re estimates for a five-week moving window, advanced by week. Associations of Re with absolute latitude, human development index, percent of the population aged <15 years, and percent of those living in rural areas in each country were assessed. Results: Time series were included for 119 of 169 available countries. There were 100 countries with influenza A and 79 with B epidemics. Median Re for both influenza A and B epidemics was 1.23 (ranges: A 1.10, 1.60; B 1.06, 1.58). Re of influenza B but not A was independently associated with absolute latitude, increasing by 0.022 (95% confidence interval 0.002, 0.043) per 10 degrees. Conclusion: The Re of influenza A and B were similar. Only the Re of influenza B was associated with country characteristics, which was increasing with distance from the equator. The approach may be suitable for continuous Re surveillance

Behavioural Markers of Air Traffic Controller Development

A key challenge when introducing new systems and technologies into Air Traffic control (ATC) is to understand levels of emerging controller proficiency ahead of scheduled implementation. Behavioural markers have been used in several complex industries to assess levels of non-technical skill; however these measures invariably focus upon the desired behaviours attained by the end of training. This research has explored how an Air Traffic Controller’s (ATCO’s) overt non-technical behaviour changes in presence and prevalence as they progress their expertise during training. Through document review, expert engagement, and most extensively direct observation of ATCOs during and after training, a number of non-technical behaviours indicative of varying proficiency have been identified. These markers were placed within a simple three-level learning and development framework. Five categories emerged across the behaviours identified; i) input and interaction with the Human Machine Interface (HMI), ii) interaction with others, iii) physical posture and body Language, iv) attitude and mood; v) communications and verbal commentary. An observation sheet containing the markers was iteratively developed, tested, and refined in various ATC environments. Both expert ATCOs undergoing system transition training, and ab-initio trainee controllers undertaking aerodrome training were followed through longitudinal study. A capped frequency count was used to record the precise presence of individual markers. Several dual-observations were also undertaken to determine inter-rater reliability and construct validity. In total, the performance of the individual markers has been evaluated across 129 real-world observations. 30 markers demonstrate reliable correlations for changing prevalence against total system exposure time and provide an original means of tracking and monitoring subtle changes in the behaviour of ATCOs, as their levels of proficiency in the task matures with new ATC systems

High Energy Gamma-Ray Emission From Blazars: EGRET Observations

We will present a summary of the observations of blazars by the Energetic Gamma Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory (CGRO). EGRET has detected high energy gamma-ray emission at energies greater than 100 MeV from more that 50 blazars. These sources show inferred isotropic luminosities as large as $3\times 10^{49}$ ergs s$^{-1}$. One of the most remarkable characteristics of the EGRET observations is that the gamma-ray luminosity often dominates the bolometric power of the blazar. A few of the blazars are seen to exhibit variability on very short time-scales of one day or less. The combination of high luminosities and time variations seen in the gamma-ray data indicate that gamma-rays are an important component of the relativistic jet thought to characterize blazars. Currently most models for blazars involve a beaming scenario. In leptonic models, where electrons are the primary accelerated particles, gamma-ray emission is believed to be due to inverse Compton scattering of low energy photons, although opinions differ as to the source of the soft photons. Hardronic models involve secondary production or photomeson production followed by pair cascades, and predict associated neutrino production.Comment: 16 pages, 7 figures, style files included. Invited review paper in "Observational Evidence for Black Holes in the Universe," 1999, ed. S. K. Chakrabarti (Dordrecht: Kluwer), 215-23