Project description:Animals need to manage the combined risks of predation and starvation in order to survive. Theoretical and empirical studies have shown that individuals can reduce predation risk by delaying feeding (and hence fat storage) until late afternoon. However, little is known about how individuals manage the opposing pressures of resource uncertainty and predation risks. We suggest that individuals should follow a two-part strategy: prioritizing the discovery of food early in the day and exploiting the best patch late in the day. Using automated data loggers, we tested whether a temporal component exists in the discovery of novel foraging locations by individuals in a mixed-species foraging guild. We found that food deployed in the morning was discovered significantly more often than food deployed in the afternoon. Based on the diurnal activity patterns in this population, overall rates of new arrivals were also significantly higher than expected in the morning and significantly lower than expected in the afternoon. These results align with our predictions of a shift from patch discovery to exploitation over the course of the day.
Project description:The COVID-19 pandemic has modified practice for patients with symptomatic aortic stenosis and could result in higher mortality rates due to treatment delays. In this clinical case series, 3 patients underwent ambulatory transcatheter aortic valve replacement (TAVR) thanks to patient and entourage willingness, careful patient selection (including a history of permanent pacemaker placement), and a minimalist procedural approach. No complications occurred during the 30-day follow-up. Performing ambulatory TAVR could reduce the clinical consequences of wait times, minimize exposure to coronavirus contamination, and reduce the use of hospital resources that might be needed for COVID-19 patients. Thanks to a scrupulous minimalist TAVR protocol, ambulatory outpatient management of aortic stenosis was possible in the context of the COVID-19 pandemic.
Project description:BackgroundClinical advantages of sutureless rapid-deployment (RD) aortic valve replacement (AVR) for severe aortic valve stenosis (AS) have not been elucidated compared with surgical (SAVR) or transcatheter (TAVR) aortic valve replacement.ObjectivesThis study sought to investigate comparative effectiveness and safety of RD-AVR compared with SAVR and TAVR in a prospective cohort of patients with severe AS.MethodsThe primary outcome was a composite of death, stroke, or rehospitalization at 12 months. Propensity score matching was used to assemble a cohort of patients with similar baseline characteristics.ResultsAmong 1,020 eligible patients, 107 (10.5%) underwent RD-AVR, 437 (42.8%) underwent SAVR, and 476 (46.7%) underwent TAVR. In the matched cohorts of RD-AVR and SAVR (n = 107), the incidence of primary composite outcome at 12 months was similar between the 2 groups (8.0% vs 10.8%, respectively; hazard ratio [HR]: 0.74; 95% confidence interval [CI]: 0.30-1.84; P = 0.52). In the matched cohorts of RD and TAVR (n = 58), the incidence of primary composite outcome at 12 months did not statistically differ between the 2 groups (9.4% vs 16.2%, respectively; HR: 0.53; 95% CI: 0.18-1.57; P = 0.25).ConclusionsIn this propensity-matched cohort of patients who underwent AVR for severe AS, we did not detect significant differences in the rates of the primary composite of death, stroke, or rehospitalization at 12 months when comparing RD-AVR with SAVR and TAVR. Because the study was underpowered, the results should be considered as hypothesis generating highlighting the need for further research. (ASAN Medical Center Aortic Valve Replacement Registry [ASAN-AVR]; NCT03298178).
Project description:BackgroundIdentifying high-risk patients who will not derive substantial survival benefit from TAVR remains challenging. Pulmonary hypertension is a known predictor of poor outcome in patients undergoing TAVR and correlates strongly with pulmonary artery (PA) enlargement on CTA. We sought to evaluate whether PA enlargement, measured on pre-procedural computed tomography angiography (CTA), is associated with 1-year mortality in patients undergoing TAVR.MethodsWe retrospectively included 402 patients undergoing TAVR between July 2012 and March 2016. Clinical parameters, including Society of Thoracic Surgeons (STS) score and right ventricular systolic pressure (RVSP) estimated by transthoracic echocardiography were reviewed. PA dimensions were measured on pre-procedural CTAs. Association between PA enlargement and 1-year mortality was analyzed. Kaplan-Meier and Cox proportional hazards regression analyses were performed.ResultsThe median follow-up time was 433 (interquartiles 339-797) days. A total of 56/402 (14%) patients died within 1 year after TAVR. Main PA area (area-MPA) was independently associated with 1-year mortality (hazard ratio per standard deviation equal to 2.04 [95%-confidence interval (CI) 1.48-2.76], p < 0.001). Area under the curve (95%-CI) of the clinical multivariable model including STS-score and RVSP increased slightly from 0.67 (0.59-0.75) to 0.72 (0.72-0.89), p = 0.346 by adding area-MPA. Although the AUC increased, differences were not significant (p = 0.346). Kaplan-Meier analysis showed that mortality was significantly higher in patients with a pre-procedural non-indexed area-MPA of ≥7.40 cm2 compared to patients with a smaller area-MPA (mortality 23% vs. 9%; p < 0.001).ConclusionsEnlargement of MPA on pre-procedural CTA is independently associated with 1-year mortality after TAVR.
Project description:Transcatheter aortic valve replacement in surgical aortic valve is a safe and effective procedure to treat patients with failed bioprosthetic surgical valves at high risk for reoperation. Performing bioprosthetic valve fracture has been shown to improve postprocedural hemodynamics of TAVR in surgical aortic valve replacement. However, specific complications related to valve fracture are becoming more common. (Level of Difficulty: Advanced.).
Project description:Circadian rhythmicity plays an important role for many aspects of honey bees' lives. However, the question whether it also affects learning and memory remained unanswered. To address this question, we studied the effect of circadian timing on olfactory learning and memory in honey bees Apis mellifera using the olfactory conditioning of the proboscis extension reflex paradigm. Bees were differentially conditioned to odours and tested for their odour learning at four different "Zeitgeber" time points. We show that learning behaviour is influenced by circadian timing. Honey bees perform best in the morning compared to the other times of day. Additionally, we found influences of the light condition bees were trained at on the olfactory learning. This circadian-mediated learning is independent from feeding times bees were entrained to, indicating an inherited and not acquired mechanism. We hypothesise that a co-evolutionary mechanism between the honey bee as a pollinator and plants might be the driving force for the evolution of the time-dependent learning abilities of bees. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00265-010-1026-9) contains supplementary material, which is available to authorized users.
Project description:Transcatheter aortic valve replacement within a degenerated surgical bioprosthetic aortic valve is increasing in frequency. We present a rare case of a patient requiring a second TAVR placed within a previous placed degenerated transcatheter aortic valve, which was implanted in a degenerated surgical bioprosthetic aortic valve. (Level of Difficulty: Advanced.).