Local temperature-sensitive mechanisms are important mediators of limb tissue hyperemia in the heat-stressed human at rest and during small muscle mass exercise.

Limb tissue and systemic blood flow increases with heat stress, but the underlying mechanisms remain poorly understood. Here, we tested the hypothesis that heat stress-induced increases in limb tissue perfusion are primarily mediated by local temperature-sensitive mechanisms. Leg and systemic temperatures and hemodynamics were measured at rest and during incremental single-legged knee extensor exercise in 15 males exposed to 1 h of either systemic passive heat-stress with simultaneous cooling of a single leg (n=8) or isolated leg heating or cooling (n=7). Systemic heat-stress increased core, skin and heated leg blood (Tb) temperatures, cardiac output and heated leg blood flow (LBF, 0.6 ± 0.1 l.min(-1); P0.05). Increased heated leg deep tissue BF was closely related to Tb (R(2) = 0.50; P0.05), despite unchanged systemic temperatures and hemodynamics. During incremental exercise, heated LBF was consistently maintained ~ 0.6 l.min(-1) higher than that in the cooled leg (P<0.01), with LBF and vascular conductance in both legs showing a strong correlation with their respective local Tb (R(2) = 0.85 and 0.95, P<0.05). We conclude that local temperature-sensitive mechanisms are important mediators in limb tissue perfusion regulation both at rest and during small-muscle mass exercise in hyperthermic humans.The invasive study was partially funded by Gatorade Sports Science Institute, PepsiCo

Weighted Fisher Discriminant Analysis in the Input and Feature Spaces

Fisher Discriminant Analysis (FDA) is a subspace learning method which minimizes and maximizes the intra- and inter-class scatters of data, respectively. Although, in FDA, all the pairs of classes are treated the same way, some classes are closer than the others. Weighted FDA assigns weights to the pairs of classes to address this shortcoming of FDA. In this paper, we propose a cosine-weighted FDA as well as an automatically weighted FDA in which weights are found automatically. We also propose a weighted FDA in the feature space to establish a weighted kernel FDA for both existing and newly proposed weights. Our experiments on the ORL face recognition dataset show the effectiveness of the proposed weighting schemes.Comment: Accepted (to appear) in International Conference on Image Analysis and Recognition (ICIAR) 2020, Springe

Telemedicine networks for acute stroke: An analysis of global coverage, gaps, and opportunities

Background:: Despite the proven efficacy of telestroke in improving clinical outcomes by providing access to specialized expertise and allowing rapid expert hyperacute stroke management and decision-making, detailed operational evidence is scarce, especially for less developed or lower income regions. Aim:: We aimed to map the global telestroke landscape and characterize existing networks. Methods:: We employed a four-tiered approach to comprehensively identify telestroke networks, primarily involving engagement with national stroke experts, stroke societies, and international stroke authorities. A carefully designed questionnaire was then distributed to the leaders of all identified networks to assess these networks’ structures, processes, and outcomes. Results:: We identified 254 telestroke networks distributed across 67 countries. High-income countries (HICs) concentrated 175 (69%) of the networks. No evidence of telestroke services was found in 58 (30%) countries. From the identified networks, 88 (34%) completed the survey, being 61 (71%) located in HICs. Network setup was highly heterogeneous, ranging from 17 (22%) networks with more than 20 affiliated hospitals, providing thousands of annual consultations using purpose-built highly specialized technology, to 11 (13%) networks with fewer than 120 consultations annually using generic videoconferencing equipment. Real-time video and image transfer was employed in 64 (75%) networks, while 62 (74%) conducting quality monitoring. Most networks established in the past 3 years were located in low- and middle-income countries (LMICs). Conclusion:: This comprehensive global survey of telestroke networks found significant variation in network coverage, setup, and technology use. Most services are in HICs, and a few services are in LMICs, although an emerging trend of new networks in these regions marks a pivotal moment in global telestroke care. The wide variation in quality monitoring practices across networks, with many failing to report key performance metrics, underscores the urgent need for standardized, resource-appropriate, quality assurance measures that can be adapted to diverse settings