Biases in comparative analyses of extinction risk: mind the gap

. Comparative analyses are used to address the key question of what makes a species more prone to extinction by exploring the links between vulnerability and intrinsic species’ traits and ⁄ or extrin- sic factors. This approach requires comprehensive species data but information is rarely available for all species of interest. As a result comparative analyses often rely on subsets of relatively few species that are assumed to be representative samples of the overall studied group. 2. Our study challenges this assumption and quantifies the taxonomic, spatial, and data type biases associated with the quantity of data available for 5415 mammalian species using the freely available life-history database PanTHERIA. 3. Moreover, we explore how existing biases influence results of comparative analyses of extinc- tion risk by using subsets of data that attempt to correct for detected biases. In particular, we focus on links between four species’ traits commonly linked to vulnerability (distribution range area, adult body mass, population density and gestation length) and conduct univariate and multivari- ate analyses to understand how biases affect model predictions. 4. Our results show important biases in data availability with c.22% of mammals completely lack- ing data. Missing data, which appear to be not missing at random, occur frequently in all traits (14–99% of cases missing). Data availability is explained by intrinsic traits, with larger mammals occupying bigger range areas being the best studied. Importantly, we find that existing biases affect the results of comparative analyses by overestimating the risk of extinction and changing which traits are identified as important predictors. 5. Our results raise concerns over our ability to draw general conclusions regarding what makes a species more prone to extinction. Missing data represent a prevalent problem in comparative anal- yses, and unfortunately, because data are not missing at random, conventional approaches to fill data gaps, are not valid or present important challenges. These results show the importance of making appropriate inferences from comparative analyses by focusing on the subset of species for which data are available. Ultimately, addressing the data bias problem requires greater investment in data collection and dissemination, as well as the development of methodological approaches to effectively correct existing biases.Peer reviewe

ПЕРШИЙ ЮВІЛЕЙ КАТЕРИНОСЛАВА ЯК ІСТОРІОГРАФІЧНЕ ЯВИЩЕ

У статті здійснена спроба вивчення історіографічного процесу у регіональному вимірі на прикладі Катеринослава.The article deals with the investigation of historiographic process in the second of XIX – at the beginning of ХХ century in a regional view on the materials of Katerinoslav

Heavy silicone oil versus standard silicone oil in as vitreous tamponade in inferior PVR (HSO Study): interim analysis

Purpose: The Heavy Silicone Oil versus Standard Silicone Oil Study (HSO study) is designed to answer the question whether a heavier-than-water tamponade improves the prognosis of eyes with proliferative vitreoretinopathy (PVR) of the lower retina. Methods: The HSO Study is a multicentre, randomized, prospective, controlled clinical trial stratified by surgeon comparing two endotamponades within a two-arm parallel-group design. Patients with inferiorly and posteriorly located PVR grade C-A6 were randomized to either HSO or standard silicone oil as a tamponading agent. The main end-point criteria are complete retinal attachment at 12 months and change in visual acuity (VA) 12 months post-operatively compared to the preoperative VA. Results: Forty-six patients treated with HSO were compared to 47 patients treated with standard silicone oil. There was no difference among the groups regarding baseline data. Three patients in the HSO and five patients in the standard silicone oil group fulfilled intraoperative exclusion criteria. There was no significant difference between both groups regarding anatomical success. Neither noninferiority nor superiority was shown with regard to final acuity. Conclusions: The HSO Study is the first randomized prospective clinical trial to compare heavy and standard silicone oil in patients with PVR of the lower retina. The intermediate results failed to demonstrate superiority of a heavy tamponade

Chronic kidney disease aggravates arteriovenous fistula damage in rats

Neointimal hyperplasia (NIH) and impaired dilatation are important contributors to arteriovenous fistula (AVF) failure. It is unclear whether chronic kidney disease (CKD) itself causes adverse remodeling in arterialized veins. Here we determined if CKD specifically triggers adverse effects on vascular remodeling and assessed whether these changes affect the function of AVFs. For this purpose, we used rats on a normal diet or on an adenine-rich diet to induce CKD and created a fistula between the right femoral artery and vein. Fistula maturation was followed noninvasively by high-resolution ultrasound (US), and groups of rats were killed on 42 and 84 days after surgery for histological and immunohistochemical analyses of the AVFs and contralateral femoral vessels. In vivo US and ex vivo morphometric analyses confirmed a significant increase in NIH in the AVFs of both groups with CKD compared to those receiving a normal diet. Furthermore, we found using histological evaluation of the fistula veins in the rats with CKD that the media shrank and their calcification increased significantly. Afferent artery dilatation was significantly impaired in CKD and the downstream fistula vein had delayed dilation after surgery. These changes were accompanied by significantly increased peak systolic velocity at the site of the anastomosis, implying stenosis. Thus, CKD triggers adverse effects on vascular remodeling in AVFs, all of which contribute to anatomical and/or functional stenosis

Chronic kidney disease aggravates arteriovenous fistula damage in rats

Neointimal hyperplasia (NIH) and impaired dilatation are important contributors to arteriovenous fistula (AVF) failure. It is unclear whether chronic kidney disease (CKD) itself causes adverse remodeling in arterialized veins. Here we determined if CKD specifically triggers adverse effects on vascular remodeling and assessed whether these changes affect the function of AVFs. For this purpose, we used rats on a normal diet or on an adenine-rich diet to induce CKD and created a fistula between the right femoral artery and vein. Fistula maturation was followed noninvasively by high-resolution ultrasound (US), and groups of rats were killed on 42 and 84 days after surgery for histological and immunohistochemical analyses of the AVFs and contralateral femoral vessels. In vivo US and ex vivo morphometric analyses confirmed a significant increase in NIH in the AVFs of both groups with CKD compared to those receiving a normal diet. Furthermore, we found using histological evaluation of the fistula veins in the rats with CKD that the media shrank and their calcification increased significantly. Afferent artery dilatation was significantly impaired in CKD and the downstream fistula vein had delayed dilation after surgery. These changes were accompanied by significantly increased peak systolic velocity at the site of the anastomosis, implying stenosis. Thus, CKD triggers adverse effects on vascular remodeling in AVFs, all of which contribute to anatomical and/or functional stenosis