Best environmental predictors of breeding phenology differ with elevation in a common woodland bird species
ECOLOGY AND EVOLUTION
Authors: Bison, Marjorie; Yoccoz, Nigel G.; Carlson, Bradley; Klein, Geoffrey; Laigle, Idaline; Van Reeth, Colin; Asse, Daphne; Delestrade, Anne
Abstract
Temperatures in mountain areas are increasing at a higher rate than the Northern Hemisphere land average, but how fauna may respond, in particular in terms of phenology, remains poorly understood. The aim of this study was to assess how elevation could modify the relationships between climate variability (air temperature and snow melt-out date), the timing of plant phenology and egg-laying date of the coal tit (Periparus ater). We collected 9 years (2011-2019) of data on egg-laying date, spring air temperature, snow melt-out date, and larch budburst date at two elevations (similar to 1,300 m and similar to 1,900 m asl) on a slope located in the Mont-Blanc Massif in the French Alps. We found that at low elevation, larch budburst date had a direct influence on egg-laying date, while at high-altitude snow melt-out date was the limiting factor. At both elevations, air temperature had a similar effect on egg-laying date, but was a poorer predictor than larch budburst or snowmelt date. Our results shed light on proximate drivers of breeding phenology responses to interannual climate variability in mountain areas and suggest that factors directly influencing species phenology vary at different elevations. Predicting the future responses of species in a climate change context will require testing the transferability of models and accounting for nonstationary relationships between environmental predictors and the timing of phenological events.
Reperfusion Into Severely Damaged Brain Tissue Is Associated With Occurrence of Parenchymal Hemorrhage for Acute Ischemic Stroke
FRONTIERS IN NEUROLOGY
Authors: Yu, Songlin; Ma, Samantha J.; Liebeskind, David S.; Qiao, Xin J.; Yan, Lirong; Saver, Jeffrey L.; Salamon, Noriko; Wang, Danny J. J.
Abstract
Background and Purpose:This study aims to quantify the reperfusion status within severely damaged brain tissue and to evaluate its relationship with high grade of hemorrhagic transformation (HT). Methods:Pseudo-continuous ASL was performed along with DWI in 102 patients within 24 h post-treatments. The infarction core was identified using ADC values <550 x 10(-6)mm(2)/s. CBF within the infarction core and its contralateral counterpart were acquired. CBF at the 25th, median, and 75th percentiles of the contralateral counterpart were used as thresholds and the ASL reperfusion volume above the threshold was labeled as vol-25, -50, and -75, respectively. Recanalization was defined according to Thrombolysis in Myocardial Infarction (TIMI) criteria. Results:Quantified reperfusion within the infarction core differed significantly in patients with complete and incomplete recanalization. In the ROC analysis for the prediction of parenchymal hematoma (PH), ASL reperfusion vol-25 had the highest area under the curve (AUC) when compared with ASL vol-50 and ASL vol-75. ASL reperfusion vol-25 had significantly higher AUC compared with ADC threshold volume in the prediction of PH (0.783 vs. 0.685,P= 0.0036) and PH-2 (0.844 vs. 0.754,P= 0.0035). In stepwise multivariate logistic regression analysis, only ASL reperfusion vol-25 emerged as an independent predictor of PH (OR = 3.51, 95% CI: 1.65-7.45,P< 0.001) and PH-2 (OR = 2.32, 95% CI: 1.13-4.76,P= 0.022). Conclusions:Increased reperfusion volume within severely damaged brain tissue is associated with the occurrence of higher grade of HT.