Repeated practice runs during on-snow training do not generate any measurable neuromuscular alterations in elite alpine skiers

Background Alpine skiers typically train using repeated practice runs requiring high bursts of muscle activity but there is little field-based evidence characterizing neuromuscular function across successive runs. Purpose To examine the impact of repeated ski runs on electromyographic activity (EMG) of the knee extensors and flexors in elite alpine skiers. Methods Nineteen national team alpine skiers were tested during regular ski training [Slalom (SL), Giant Slalom (GS), Super Giant Slalom and Downhill (Speed)] for a total of 39 training sessions. The surface EMG of the vastus lateralis (VL), rectus femoris (RF), vastus medialis (VM), biceps femoris (BF) and semimembranosus/semitendinosus (SMST) muscles was continuously recorded along with right knee and hip angles. The EMG root mean square signal was normalized to a maximal voluntary contraction (%MVC). The first and fourth runs of the training session were compared. Results There was no meaningful main effect of run on EMG relative activation time or mean power frequency beyond the skier's intrinsic variability. However, EMG activity of the vastii increased from the first to the fourth run in SL [VM, ~+3%MVC for IL and outside leg (OL), p = 0.035)], speed (VL, IL:+6%/OL:+11%, p = 0.015), and GS (VM, IL:0/OL:+7%, p < 0.001); the later with an interaction with leg (p < 0.001) due to a localized increase on the OL. The run time and turn time did not change from the first to the fourth run. There were no meaningful changes in angular velocities, amplitude of movement, or maximal and minimal angles. Conclusion Neuromuscular activity remains highly stable in elite skiers with low variability across four runs

Mediterranean hurricanes: large-scale environment and convective and precipitating areas from satellite microwave observations

Subsynoptic scale vortices that have been likened to tropical cyclones or polar lows (medicanes) are occasionally observed over the Mediterranean Sea. Generated over the sea, they are usually associated with strong winds and heavy precipitation and thus can be highly destructive in islands and costal areas. Only an accurate forecasting of such systems could mitigate these effects. However, at the moment, the predictability of these systems remains limited. &lt;br&gt;&lt;br&gt; Due to the scarcity of conventional observations, use is made of NOAA/MetOp satellite observations, for which advantage can be taken of the time coverage differences between the platforms that carry it, to give a very complete temporal description of the disturbances. A combination of AMSU-B (Advanced Microwave Sounding Unit-B)/MHS (Microwave Humidity Sounder) observations permit to investigate precipitation associated with these systems while coincident AMSU-A (Advanced Microwave Sounding Unit-A) observations give insights into the larger synoptic-scale environment in which they occur. &lt;br&gt;&lt;br&gt; Three different cases (in terms of intensity, location, trajectory, duration, and periods of the year – May, September and December, respectively) were investigated. Throughout these time periods, AMSU-A observations show that the persisting deep outflow of cold air over the sea together with an upper-level trough upstream constituted a favourable environment for the development of medicanes. AMSU-B/MHS based diagnostics show that convection and precipitation areas are large in the early stage of the low, but significantly reduced afterwards. Convection is maximum just after the upper-level trough, located upstream of cold mid-tropospheric air, reached its maximum intensity and acquired a cyclonic orientation

H2020 Copernicus CalVal Solution CCVS

The objective of the Copernicus H2020 Cal/Val Solution (CCVS) project is to define a holistic solution for all Copernicus Sentinel missions to overcome current limitations for both current and upcoming Sentinel-missions. This includes improved calibration of currently operational or planned Copernicus Sentinel sensors and the validation of Copernicus core products generated by the payload ground segment. While high-resolution optical missions are out of scope of the project, most of the recommendations coming from the project could be applicable or beneficial to these missions. This presentation will focus on those aspects and highlight possible synergies between Copernicus missions and high-resolution missions. The first aspect concerns R&D on models. Models of natural targets (PICS, Moon, Deep Convective Clouds) need to be further improved in terms of spectral coverage, SI traceability and uncertainty estimates. Validation methodologies using models of complex scenes (e.g. urban or vegetated scenes) with 3D Radiative Transfer should be developed. Progress on atmospheric Radiative Transfer Models is critical to improve uncertainty of surface reflectance measurements. Development of open-source models and cross-comparison activities should be encouraged, and community-agreed guidelines on best practices for modelling should be issued. Validation of surface reflectance is currently limited by the lack of suitable reference measurements (FRM). The CCVS project supports the development of an operational network of automatic hyperspectral radiometers on a set of representative and fully characterized sites (including BRDF and spatial homogeneity). The measurements should be SI traceable and provided with uncertainties. These sites should be regularly compared with a well characterised travelling standard that is controlled by across network body. Such network could be of interest for VHR-missions for the radiometry CalVal activities. Regarding geometry CalVal, in addition to the project support of a public reference grid such as the Sentinel-2 GRI at Level-1C, the project identified a lack of suitable geometric reference for nigh-time thermal infra-red imaging. R&D activities should explore the possible use of reference features such as gas flares or contrasted scenes (water/land interfaces). Finally, the reliability of cloud and cloud shadow masks is an important factor for the quality of optical surface measurements. Therefore, any improvement on the masking algorithms would be an asset to the VHR-missions products. To achieve this objective, it could be useful to develop a public cloud mask reference database and to harmonize validation methodologies

A Holistic Perspective on the Calibration and Validation of Sentinel-2 L2A products: Contribution From the CCVS Project

In this presentation, we report on the preliminary findings of the H2020 project “Copernicus Cal/Val Solution” (CCVS), whose objective is to define a holistic solution to the cal/val of the Copernicus Sentinel missions. We focus more specifically on synergies of the Sentinel-2 mission with other Sentinel or third-party missions, in terms of cal/val requirements as well as reference data sources. Regarding the first aspect, CCVS will consolidate cal/val requirements for all missions with a unified approach. For instance, we compare validation requirements for Sentinel-2 L2A AOD and Water Vapour products to other optical missions like Sentinel-3 OLCI and SLSTR, as well as atmospheric composition missions. In addition, user-driven inter-operability requirements could lead to specific calibration or validation needs. A first example concerns the radiometric inter-calibration between Sentinel-2A and B, which could be ensured with better accuracy than the absolute calibration of either satellites. Geometric co-registration with other optical missions like Landsat could be also monitored. In terms of data sources, CCVS will first establish a survey of existing sources, including natural targets and in-situ data acquired in the frame of systematic measurement programs or ad-hoc campaigns. In a second step, we investigate potential data sources needed for calibration and validation, with a specific focus on directional surface reflectance and cloud mask

Copernicus Sentinel-2 Collection-1: A Consistent Dataset of Multispectral Imagery with enhanced Quality

The Copernicus Sentinel-2 satellite mission, with its Sentinel-2A and Sentinel-2B units, offers since several years now a massive quantitative and qualitative resource for the Earth Observation community. Since the launch of Sentinel-2A in 2015, and Sentinel-2B in 2017, many lessons have been learnt leading to continuous improvements of the radiometric and the geometric performances. However, the current archive is composed of heterogenous processing baselines with inconsistent product formats and uneven data quality, which limits its use for multi-temporal monitoring applications. To overcome this limitation, the Copernicus program has undertaken a complete reprocessing with the latest processing baseline (05.00). It concerns the L1C (Top-OfAtmosphere reflectance) and L2A (Surface Reflectance) products. This paper recalls the features of Collection-1 products and gives an overview of the first validation results

Copernicus Cal/Val Solution - D3.2 - Recommendations for R&D on Cal/Val Methods

This document presents a gap analysis of the methods used in the calibration and validation of Earth Observation satellites relevant to the Copernicus programme and suggests recommendations for the research and developments required to fulfil this gap when/where possible. The document identifies the gaps and limitations of the CalVal methods, used for calibration and validation (CalVal) activities for the current Copernicus missions. It will also address the development needs for future Copernicus missions. Four types of missions are covered based on the division used in the rest of the CCVS project: optical, altimetry, radar and microwave and atmospheric composition. Finally, it will give a prioritized list of recommendations for R&D activities on the CalVal methods. The information included is mainly collected from the deliverables of work packages 1 and 2 in the CCVS project and from the consortium experts in CalVal activities

Association between thermal responses, medical events, performance, heat acclimation and health status in male and female elite athletes during the 2019 Doha World Athletics Championships

Please read abstract in the article.The World Athletics Health and Science Department.http://bjsm.bmj.comhj2022Sports Medicin

Regional and experiential differences in surgeon preference for the treatment of cervical facet injuries: a case study survey with the AO Spine Cervical Classification Validation Group

Purpose: The management of cervical facet dislocation injuries remains controversial. The main purpose of this investigation was to identify whether a surgeon’s geographic location or years in practice influences their preferred management of traumatic cervical facet dislocation injuries. Methods: A survey was sent to 272 AO Spine members across all geographic regions and with a variety of practice experience. The survey included clinical case scenarios of cervical facet dislocation injuries and asked responders to select preferences among various diagnostic and management options. Results: A total of 189 complete responses were received. Over 50% of responding surgeons in each region elected to initiate management of cervical facet dislocation injuries with an MRI, with 6 case exceptions. Overall, there was considerable agreement between American and European responders regarding management of these injuries, with only 3 cases exhibiting a significant difference. Additionally, results also exhibited considerable management agreement between those with ≤ 10 and &gt; 10&nbsp;years of practice experience, with only 2 case exceptions noted. Conclusion: More than half of responders, regardless of geographical location or practice experience, identified MRI as a screening imaging modality when managing cervical facet dislocation injuries, regardless of the status of the spinal cord and prior to any additional intervention. Additionally, a majority of surgeons would elect an anterior approach for the surgical management of these injuries. The study found overall agreement in management preferences of cervical facet dislocation injuries around the globe

Effect of surgical experience and spine subspecialty on the reliability of the {AO} Spine Upper Cervical Injury Classification System

OBJECTIVE The objective of this paper was to determine the interobserver reliability and intraobserver reproducibility of the AO Spine Upper Cervical Injury Classification System based on surgeon experience (&lt; 5 years, 5–10 years, 10–20 years, and &gt; 20 years) and surgical subspecialty (orthopedic spine surgery, neurosurgery, and "other" surgery). METHODS A total of 11,601 assessments of upper cervical spine injuries were evaluated based on the AO Spine Upper Cervical Injury Classification System. Reliability and reproducibility scores were obtained twice, with a 3-week time interval. Descriptive statistics were utilized to examine the percentage of accurately classified injuries, and Pearson’s chi-square or Fisher’s exact test was used to screen for potentially relevant differences between study participants. Kappa coefficients (κ) determined the interobserver reliability and intraobserver reproducibility. RESULTS The intraobserver reproducibility was substantial for surgeon experience level (&lt; 5 years: 0.74 vs 5–10 years: 0.69 vs 10–20 years: 0.69 vs &gt; 20 years: 0.70) and surgical subspecialty (orthopedic spine: 0.71 vs neurosurgery: 0.69 vs other: 0.68). Furthermore, the interobserver reliability was substantial for all surgical experience groups on assessment 1 (&lt; 5 years: 0.67 vs 5–10 years: 0.62 vs 10–20 years: 0.61 vs &gt; 20 years: 0.62), and only surgeons with &gt; 20 years of experience did not have substantial reliability on assessment 2 (&lt; 5 years: 0.62 vs 5–10 years: 0.61 vs 10–20 years: 0.61 vs &gt; 20 years: 0.59). Orthopedic spine surgeons and neurosurgeons had substantial intraobserver reproducibility on both assessment 1 (0.64 vs 0.63) and assessment 2 (0.62 vs 0.63), while other surgeons had moderate reliability on assessment 1 (0.43) and fair reliability on assessment 2 (0.36). CONCLUSIONS The international reliability and reproducibility scores for the AO Spine Upper Cervical Injury Classification System demonstrated substantial intraobserver reproducibility and interobserver reliability regardless of surgical experience and spine subspecialty. These results support the global application of this classification system

Circulation générale océanique et variabilité à méso-échelle en Méditerranée Orientale: approche numérique

The circulation in the eastern Mediterranean basin has been studied using a general circulation model with very high horizontal resolution, climatologies, in-situ and remote sensed observations. A thorough validation of the model shows a good agreement of the various water masses. The surface circulation is also in good agreement with recent circulation schemes derived from observations. For instance, the main part of the Atlantic inflow follows the African coast and forms a permanent and intense coastal jet along the Libyan coasts, rather than the Mid Mediterranean Jet described few years ago by several authors. The well known mesoscale structures (Egyptian eddies, Ierapetra...) are also well reproduced. In good agreement with altimetric and SST observations, the model shows that energetic mesoscale eddies dominate the surface circulation in the south of the Levantine basin. Mesoscale eddies are more energetic in summer than in the whole of the basin. In addition, simulations allow a detailed analysis of the life cycle of these eddies and how they are able to control the mean circulation. Depending on the position and development of these eddies, different circulation regimes are observed. In particular, eddies in the Levantine basin (Egyptian eddies, Lattaquia, Ierapetra) can block and force offshore bifurcations of the coastal surface Atlantic inflow.L'étude de la circulation dans le bassin Est de la Mer Méditerranée a été abordée par une analyse conjointe de simulations numériques réalisées avec un modèle à très haute résolution horizontale, de climatologies et d'observations in-situ et satellitaires. Une validation approfondie du modèle montre un bon accord entre les différentes masses d'eau. La circulation de surface est, elle aussi, en bon accord avec les schémas de circulation récents. Ainsi, la majeure partie de l'eau atlantique suit la côte africaine et forme un jet côtier intense au niveau de la côte libyenne, plutôt que le Mid Mediterranean Jet décrit il y a quelques années par plusieurs auteurs. Les structures de mésoéchelle bien répertoriées (tourbillons d'Egypte, Ierapetra, ...)sont également correctement reproduites. En accord avec des observations par satellite, le modèle montre que des tourbillons de mésoéchelle très énergétiques dominent la circulation de surface dans le sud du bassin Levantin. Les tourbillons de mésoéchelle sont plus énergiques en été qu'en hiver dans l'ensemble du bassin. Les simulations permettent en outre une analyse détaillée du cycle de vie de ces tourbillons et comment ils sont susceptibles d'affecter la circulation moyenne. Selon la position et le développement des tourbillons, des différents régimes de la circulation peuvent être reproduits. Notamment, les tourbillons du bassin Levantin (Tourbillons egyptiens, Lattaquié, Ierapetra) peuvent entraîner des blocages et bifurcations vers le large de l'inflow côtier d'eau atlantique de surface