A simple method for assessing the completeness of a geographic range size estimate
GLOBAL ECOLOGY AND CONSERVATION
Authors: Gupta, Garima; Dunn, Jonathon; Sanderson, Roy; Fuller, Richard; McGowan, P. J. K.
Abstract
Measuring geographic range size is a fundamental part of ecology and conservation. Geographic range size is used as a criterion by the IUCN Red List of Threatened Species in estimating species extinction risk. Yet the geographic distributions of many threatened species are poorly documented, and it is often unclear whether a geographic range size estimate is complete. Here we use a large and near-exhaustive database of species occurrences to (i) estimate extent of occurrence (a measure of geographic range size routinely used in Red List assessments), and (ii) develop a method to assess whether our estimate for each species is complete. We use an extensive database of point locality records for 24 Himalayan Galliformes, a group of highly threatened bird species. We examine the chronological pattern of increase of geographic range size estimates and compare this accumulation curve with a null model generated by performing 1000 iterations for each species using the point locality information in random order. Using Generalised Estimation Equations (GEE) and Generalised Least Square (GLS), we show that estimates of geographic range size for most species has now asymptoted, and that the range size estimates have improved more rapidly over time than expected by chance, suggesting relatively efficient sampling over time. The approach used in this study can be used as a simple method for assessing the completeness of a geographic range size estimates for any taxon. (C) 2019 The Authors. Published by Elsevier B.V.
Left ventricular speckle tracking echocardiographic evaluation before and after TAVI
ECHO RESEARCH AND PRACTICE
Authors: Tsampasian, Vasiliki; Panoulas, Vasileios; Jabbour, Richard J.; Ruparelia, Neil; Malik, Iqbal S.; Hadjiloizou, Nearchos; Frame, Angela; Sen, Sayan; Sutaria, Nilesh; Mikhail, Ghada W.; Nihoyannopoulos, Petros
Abstract
Aims: To assess left ventricular (LV) function before and after transcatheter aortic valve implantation (TAVI) using conventional echocardiographic parameters and global longitudinal LV strain (GLS) and compare outcomes between Edwards S3 and Evolut R valves. Methods and results: Data were collected for consecutive patients undergoing TAVI at Hammersmith hospital between 2015 and 2018. Of the 303 patients, those with coronary artery disease and atrial fibrillation were excluded leading to a total of 85 patients, which constituted our study group. The mean follow-up was 49 +/- 39 days. In total, 60% of patients were treated with Edwards S3 and 40% Evolut R. TAVI resulted in an early improvement of GLS (-13.96 to -15.25%, P = 0.01) but not ejection fraction (EF) (47.6 to 50.1%, P = 0.09). LV mass also improved, especially in patients with marked baseline LV hypertrophy (P < 0.001). There were no appreciable differences of LV function improvement and overall LV remodelling after TAVI between the two types of valves used (P = 0.14). Conclusions: TAVI results in reverse remodelling and improvement of GLS, especially in patients with impaired baseline LV function. There were no differences in the extent of LV function improvement between Edwards S3 and Evolut R valves but there was a greater incidence of aortic regurgitation with Evolut R.