Characterisation of the photolytic HONO-source in the atmosphere simulation chamber SAPHIR

HONO formation has been proposed as an important OH radical source in simulation chambers for more than two decades. Besides the heterogeneous HONO formation by the dark reaction of NO₂ and adsorbed water, a photolytic source has been proposed to explain the elevated reactivity in simulation chamber experiments. However, the mechanism of the photolytic process is not well understood so far. As expected, production of HONO and NO_x was also observed inside the new atmospheric simulation chamber SAPHIR under solar irradiation. This photolytic HONO and NO_x formation was studied with a sensitive HONO instrument under reproducible controlled conditions at atmospheric concentrations of other trace gases. It is shown that the photolytic HONO source in the SAPHIR chamber is not caused by NO₂ reactions and that it is the only direct NO_y source under illuminated conditions. In addition, the photolysis of nitrate which was recently postulated for the observed photolytic HONO formation on snow, ground, and glass surfaces, can be excluded in the chamber. A photolytic HONO source at the surface of the chamber is proposed which is strongly dependent on humidity, on light intensity, and on temperature. An empirical function describes these dependencies and reproduces the observed HONO formation rates to within 10%. It is shown that the photolysis of HONO represents the dominant radical source in the SAPHIR chamber for typical tropospheric O₃/H₂O concentrations. For these conditions, the HONO concentrations inside SAPHIR are similar to recent observations in ambient air

Liquefied natural gas expansion plans in Germany: The risk of gas lock-in under energy transitions

The German energy transition has been hailed as a role model for climate action. However, plans for the construction of three large-scale Liquefied Natural Gas (LNG) import terminals are receiving strong state support. This is inconsistent with Germany’s climate targets, which require a reduction rather than expansion of natural gas consumption. In our paper, we aim to unpack the connection between the risk of natural gas lock-in and the energy transition. We analyse the co-evolution of the techno-economic, socio-technical and political realms of the German natural gas sector and influence of actors within that process. We use a combination of energy system and interview data, and introduce a new approach to triangulate material and actor analysis. We show that four natural gas lock-in mechanisms cause the support for LNG in Germany: (A) the geopolitical influence from the United States, combined with (B) security of supply concerns due to the planned coal and nuclear phase-out, (C) pressure from a wide variety of state and private sector actors, and (D) sunk investments in existing gas infrastructure. Two additional mechanisms supporting the strong position of natural gas are (E) the strength of the emerging synthetic gas niche, and (F) weak opposition against LNG and natural gas. We highlight the severely overlooked lock-in potential and related emissions, which could complicate and decelerate energy transitions as more countries reach a more advanced phase of the energy transition

The Effects of Lower-Extremity Plyometric Training on Soccer-Specific Outcomes in Adult Male Soccer Players:A Systematic Review and Meta-Analysis

BACKGROUND: Plyometric training is a specific form of strength training that is used to improve the physical performance of athletes. An overview of the effects of plyometric training on soccer-specific outcomes in adult male soccer players is not available yet. PURPOSE: To systematically review and meta-analyze the effects of plyometric training on soccer-specific outcome measures in adult male soccer players and to identify which programs are most effective. METHODS: PubMed, Embase/Medline, Cochrane, PEDro, and Scopus were searched. Extensive quality and risk of bias assessments were performed using the Cochrane ROBINS 2.0 for randomized trials. A random effects meta-analysis was performed using Cochrane Review Manager 5.3. RESULTS: Seventeen randomized trials were included in the meta-analysis. The impact of plyometric training on strength, jump height, sprint speed, agility, and endurance was assessed. Only jump height, 20-m sprint speed, and endurance were significantly improved by plyometric training in soccer players. Results of the risk of bias assessment of the included studies resulted in overall scores of some concerns for risk of bias and high risk of bias. CONCLUSION: This review and meta-analysis showed that plyometric training improved jump height, 20-m sprint speed, and endurance, but not strength, sprint speed over other distances, or agility in male adult soccer players. However, the low quality of the included studies and substantial heterogeneity means that results need to be interpreted with caution. Future high-quality research should indicate whether or not plyometric training can be used to improve soccer-specific outcomes and thereby enhance performance

Are Off-Field Activities an Underestimated Risk for Hamstring Injuries in Dutch Male Amateur Soccer Players? An Exploratory Analysis of a Prospective Cohort Study

Purpose The purpose of this study was to explore what extent male amateur soccer players participate in off-field activities and whether these off-field activities are associated with the development of hamstring injuries. Methods Amateur soccer players (n = 399) from first-class selection teams (n = 32) filled out a baseline screening questionnaire concerning off-field activities (i.e., work and study type and hours, traveling time, sleep, energy costs, and time spent on other activities) and their history of hamstring injury as a part of a cluster-randomized controlled trial. Throughout one competition, the players reported weekly their hamstring injuries, which were verified by medical/technical staff. Multivariable Firth corrected logistic regression models were used to explore associations between off-field activities and hamstring injuries. Results Sixty-five hamstring injuries were recorded. Previous injury was significantly associated with hamstring injuries (OR ranging from 1.94 [95% CI 1.45–2.61] to 2.02 [95% CI 1.49–2.73]), but off-field activities were not. Conclusion Although amateur soccer players spent a relatively large amount of time on off-field activities, we did not find off-field activities measured at baseline to be associated with hamstring injuries in the subsequent competitive soccer season. In contrast, previous hamstring injury was found to be strongly associated with (recurrent) hamstring injuries

Adherence to an injury prevention program in male amateur football players is affected by players' age, experience and perceptions

Objectives Adherence to injury prevention programmes in football remains low, which is thought to drastically reduce the effects of injury prevention programmes. Reasons why (medical) staff and players implement injury prevention programmes, have been investigated, but player's characteristics and perceptions about these programmes might influence their adherence. Therefore, this study investigated the relationships between player's characteristics and adherence and between player's perceptions and adherence following an implemented injury prevention programme. Methods Data from 98 of 221 football players from the intervention group of a cluster randomised controlled trial concerning hamstring injury prevention were analysed. Results Adherence was better among older and more experienced football players, and players considered the programme more useful, less intense, more functional and less time-consuming. Previous hamstring injuries, educational level, the programme's difficulty and intention to continue the exercises were not significantly associated with adherence. Conclusion These player's characteristics and perceptions should be considered when implementing injury prevention programmes

Monitoring the recovery-stress states of athletes: Psychometric properties of the Acute Recovery and Stress Scale and Short Recovery and Stress Scale among Dutch and Flemish Athletes

The Acute Recovery and Stress Scale (ARSS) and the Short Recovery and Stress Scale (SRSS) are recently-introduced instruments to monitor recovery and stress processes in athletes. In this study, our aims were to replicate and extend previous psychometric assessments of the instruments, by incorporating recovery and stress dimensions into one model. Therefore, we conducted five confirmatory factor analyses (CFA) and determined structural validity, internal consistency, cross-cultural validity, and construct validity. Dutch and Flemish athletes (N=385, 213 females, 170 males, 2 others, 21.03±5.44 years) completed the translated ARSS and SRSS, the Recovery Stress Questionnaire for Athletes (RESTQ-Sport-76), and information on their last training. There was a good model fit for the replicated CFA, sub-optimal model fit for the models that incorporated recovery and stress into one model, and satisfactory internal consistency (α=.75 – .87). The correlations within and between the ARSS and SRSS, as well as between the ARSS/SRSS and the RESTQ-Sport-76 (r=.31 – -.77 for the ARSS, r=.28 – -.63 for the SRSS) and information of their last training also supported construct validity. The combined findings support the use of the ARSS and SRSS to assess stress and recovery in sports-related research and practice

A Novel Method to Increase LinLog CMOS Sensors’ Performance in High Dynamic Range Scenarios

Images from high dynamic range (HDR) scenes must be obtained with minimum loss of information. For this purpose it is necessary to take full advantage of the quantification levels provided by the CCD/CMOS image sensor. LinLog CMOS sensors satisfy the above demand by offering an adjustable response curve that combines linear and logarithmic responses. This paper presents a novel method to quickly adjust the parameters that control the response curve of a LinLog CMOS image sensor. We propose to use an Adaptive Proportional-Integral-Derivative controller to adjust the exposure time of the sensor, together with control algorithms based on the saturation level and the entropy of the images. With this method the sensor’s maximum dynamic range (120 dB) can be used to acquire good quality images from HDR scenes with fast, automatic adaptation to scene conditions. Adaptation to a new scene is rapid, with a sensor response adjustment of less than eight frames when working in real time video mode. At least 67% of the scene entropy can be retained with this method

Adherence to an injury prevention program in male amateur football players is affected by players’ age, experience and perceptions

OBJECTIVES : Adherence to injury prevention programmes in football remains low, which is thought to drastically reduce the effects of injury prevention programmes. Reasons why (medical) staff and players implement injury prevention programmes, have been investigated, but player’s characteristics and perceptions about these programmes might influence their adherence. Therefore, this study investigated the relationships between player’s characteristics and adherence and between player’s perceptions and adherence following an implemented injury prevention programme. METHODS : Data from 98 of 221 football players from the intervention group of a cluster randomised controlled trial concerning hamstring injury prevention were analysed. RESULTS : Adherence was better among older and more experienced football players, and players considered the programme more useful, less intense, more functional and less time-consuming. Previous hamstring injuries, educational level, the programme’s difficulty and intention to continue the exercises were not significantly associated with adherence. CONCLUSION : These player’s characteristics and perceptions should be considered when implementing injury prevention programmes.https://bmjopensem.bmj.comhj2022Sports Medicin