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Purpose: To investigate the effects of a repeated-sprint training in hypoxia induced by voluntary hypoventilation at low lung volume (RSH-VHL) including end-expiratory breath holding (EEBH) of maximal duration. Methods: Over a 4-week period, twenty elite judo athletes (10 women and 10 men) were randomly split into two groups to perform 8 sessions of rowing repeated-sprint exercise either with RSH-VHL (each sprint with maximal EEBH) or with unrestricted breathing (RSN, 10-s sprints). Before (Pre-), 5 days after (Post-1) and 12 days after (Post-2) the last training session, participants completed a repeated-sprint ability (RSA) test on a rowing ergometer (8 × 25-s "all-out" repetitions interspersed with 25 s of passive recovery). Power output (PO), oxygen uptake, perceptual-motor capacity (turning off a traffic light with a predetermined code), cerebral (Δ[Hbdiff]) and muscle (Δ[Hb/Mb]diff) oxygenation, cerebral total haemoglobin concentration (Δ[THb]) and muscle total haemoglobin/myoglobin concentration (Δ[THb/Mb]) were measured during each RSA repetition and/or recovery period. Results: From Pre-to Post-1 and Post-2, maximal PO, mean PO (MPO) of the first half of the test (repetitions 1–4), oxygen uptake, end-repetition cerebral Δ[Hbdiff] and Δ[THb], end-repetition muscle Δ[Hb/Mb]diff and Δ[THb/Mb] and perceptual-motor capacity remained unchanged in both groups. Conversely, MPO of the second half of the test (repetitions 5–8) was higher at Post-1 than at Pre-in RSH-VHL only (p < 0.01), resulting in a lower percentage decrement score over the entire RSA test (20.4% ± 6.5% vs. 23.9% ± 7.0%, p = 0.01). Furthermore, MPO (5–8) was greater in RSH-VHL than in RSN at Post-1 (p = 0.04). These performance results were accompanied by an increase in muscle Δ[THb/Mb] (p < 0.01) and a concomitant decrease in cerebral Δ[THb] (p < 0.01) during the recovery periods of the RSA test at Post-1 in RSH-VHL. Conclusion: Four weeks of RSH-VHL including maximal EEBH improved the ability of elite judo athletes to repeat high-intensity efforts. The performance improvement, observed 5 days but not 12 days after training, may be due to enhanced muscle perfusion. The unchanged oxygen uptake and the decrease in cerebral regional blood volume observed at the same time suggest that a blood volume redistribution occurred after the RSH-VHL intervention to meet the increase in muscle perfusion. [ABSTRACT FROM AUTHOR]

The growth of a city is typically accompanied by densification and sprawl, the former through verticalization, urban renewal, and the filling in of empty spaces. All of these activities extend and intensify the urban heat island (UHI), which is quantified in this study as the difference in daily minimum temperature between urban and rural areas. Here, we investigate this phenomenon in the area of Rennes (France) and 17 surrounding cities using the Rennes Urban Network which comprises 93 weather stations. This study aims to 1) determine the optimal method for spatializing UHI in Rennes, France, 2) estimate and spatialize the UHI in the small peri-urban cities surrounding Rennes. For this, we model mean UHI and intense UHI using three methods of interpolation--multi-linear regression (MLR), ordinary kriging (OK), and regression kriging (RK)--based on data from 2022. We find that the RK method is the most suitable overall, with an RMSE of 0.11°C for mean UHI and 0.25°C for intense UHI. This approach allows stochasticity to be taken into account, and thus provides a better representation of UHI variation within Rennes and its peri-urban cities. [ABSTRACT FROM AUTHOR]

The Ediacaran of eastern Newfoundland preserves the world's oldest known eumetazoan body fossils, as well as the earliest known record of fossilized muscular tissue. Re-examination of the holotype of the eight-armed Haootia quadriformis in terms of its morphology, the arrangement of its muscle filament bundles, and hitherto undescribed aspects of its anatomy support its interpretation as a crown staurozoan. We also document several new fossils preserving muscle tissue with a different muscular architecture to Haootia, but with only four arms. This new material allows us to describe a new crown group staurozoan, Mamsetia manunis gen. et sp. nov. This work confirms the presence of crown group medusozoan cnidarians of the Staurozoa in the Ediacaran of Newfoundland circa 565 Ma. [ABSTRACT FROM AUTHOR]