Search

High-resolution sedimentological and geochronological investigations of paleochannel systems in the Ried Central d'Alsace (northeastern France) allow for the reconstruction of the late glacial and Holocene fluvial evolution of this section of the Upper Rhine alluvial plain. During the Oldest Dryas, the landscape featured a dominant braided Rhine system and, to a lesser extent, a braided Fecht system. The shift to the Bølling-Allerød saw a narrowing of the Rhine's active channel belt, the development of a complex channel pattern, and the genesis of the Ill River. The river channel patterns remained unchanged during the Younger Dryas. In the Early Holocene, the Rhine's active belt narrowed further, and the Rhine and Ill Rivers developed braided-anastomosing and anastomosing channel patterns, respectively. Throughout the Holocene, both rivers maintained their channel patterns while migrating east and west across the alluvial plain, respectively. In the late glacial, fluvial dynamics in this section of the Upper Rhine plain were primarily influenced by climate-related environmental and hydrogeomorphological changes. Conversely, during the Holocene, the evolution of the fluvial hydrosystems was driven by a complex interaction of climatic and non-climatic factors, including human activity at the catchment scale, alluvial plain architecture, and local neotectonics. [ABSTRACT FROM AUTHOR]

Introduction: The pupil light reflex (photomotor reflex) has a duration of 3.5 s and is a highly reproducible measurement. Conventionally, the autonomic nervous system (ANS) activity evaluated by this reflex does not consider the viscoelasticity of the iris muscles. This study aims to detect differences in reflex autonomic activity in a supine position with parameters derived from the Kelvin-Voigt viscoelastic model in two distinct groups of elite athletes. Method: Groups formed using a dendrogram analysis based on basal autonomic activity assessed with heart rate variability. Heart rate variability was measured, and the photomotor reflex was modeled. Results: The model showed a high degree of adjustment to the photomotor reflex (r2 = 0.99 ± 0.01). The impulse 3, an indicator of reflex sympathetic activity, revealed a significantly higher activity (1= 0.05) in the [sympa/para]+ group compared to the [sympa/para] group. This result was further supported by a greater relative total redilation amplitude (1 = 0.05) and a shorter duration of 75% redilation (= 0.01). Finally, the relative total redilation amplitude exhibited a significant correlation with the linear stiffness constant (= 0.001) and the maximum redilation speed with restoring force (1 = 0.001). Discussion: These results indicate that (i) the photomotor reflex can detect an alteration of the reflex autonomic activity specific to each of the two branches of the ANS (ii) the viscoelastic properties of the iris muscles play a significant role in the energy storage-restitution mechanisms during the photomotor reflex. This approach could allow athletes to benefit from reduced time spent in the analysis of ANS activity, potentially making it an almost daily and automated process. [ABSTRACT FROM AUTHOR]

Purpose: To present training load (TL) and heart-rate variability (HRV) in an elite sprinter monitored before, during, and after a COVID-19 infection until successful return to performance. Methods: TL, subjective morning fatigue (MF), and supine HRV were monitored during a 12-week period. Results: During a high-TL period (training camp), MF and heart rate increased and vagally mediated HRV variables decreased. MF increased and stayed high 3 days after the camp despite decrease in TL. In contrast, 4 days after the camp, heart rate decreased and vagally mediated HRV variables increased, reflecting parasympathetic hyperactivity. Elevated MF and suboptimal training performance led to a PCR test decision, which returned positive. After a 10-day training suspension, TL was progressively increased with low MF and high vagal tone. The athlete was able to return to competition 17 days after medical clearance for return to participation and 1 week later beat his indoor 60-m personal best. Conclusions: In this athlete, COVID-19 infection induced parasympathetic hyperactivity with subjective fatigue. This case report presents how performance capacity was only negatively influenced by a COVID-19 infection in the short term, with a quick and successful return to performance, thanks to state-of-the-art medical management. This highlights the importance of TL and HRV monitoring in return-to-participation and return-to-competition decisions. [ABSTRACT FROM AUTHOR]

This article emphasizes the importance of considering the vertical dimension in socio-hydrosystem studies, particularly in relation to groundwater and subsurface flows. The authors argue that vertical connectivity has often been overlooked in previous research and call for better integration of the vertical dimension in socio-hydrological frameworks. They highlight the social and environmental implications of subsurface flows, including impacts on river ecosystems and water quality. The article also discusses the hyporheic zone, the interface between aquifers and rivers, and its importance in understanding and managing water resources. Overall, the article emphasizes the need for interdisciplinary research and a more inclusive and equitable approach to water resource management. [Extracted from the article]

Purpose: To report the changes in the training characteristics, performance, and heart-rate variability (HRV) of the world's most successful male biathlete of the last decade. Method: During the analyzed 11-year (2009–2019) period, the participant won 7 big crystal globes, corresponding to the winner of the International Biathlon Union World Cup. The training characteristics are reported as yearly volume (in hours) of low-intensity training (LIT), moderate- and high-intensity training, and speed and strength training. Performance was quantified by the number of World Cup top-3 positions per season. HRV was expressed as low- and high-frequency spectral power (in milliseconds squared), root-mean-square difference of successive R–R interval (in milliseconds), and heart rate (in beats per minute). Results: The training volume increased from 530 to ∼700 hours per year in 2009–2019, with a large polarization in training intensity distribution (ie, LIT 86.3% [2.9%]; moderate-intensity training 3.4% [1.5%]; high-intensity training 4.0% [0.7%]; strength 6.3% [1.6%]). The number of top-3 positions increased from 2 to 24–26 in 2009–2018 but decreased to 6 in 2019. The mean supine values in the root-mean-square difference of successive R–R interval and high-frequency spectral power divided by heart rate increased until 2015, which were stable over 2016–2018 but decreased in 2019. The number of top-3 positions was related to the total (r =.66, P =.02) and LIT (r =.92, P <.001) volume and to several markers of supine parasympathetic activity. Conclusion: The improvement in performance of the participant was mainly determined by the progressive increase in training volume, especially performed at low intensity, and was correlated to parasympathetic activity markers. This case study confirms the effectiveness of the training method, with a large amount of LIT in an elite endurance athlete, and of regular HRV monitoring. [ABSTRACT FROM AUTHOR]