Grass Surface Research Articles

Epidemiology of Anterior Cruciate Ligament Injury on Natural Grass Versus Artificial Turf in Soccer: 10-Year Data From the National Collegiate Athletic Association Injury Surveillance System.

Background:Anterior cruciate ligament (ACL) injury is prevalent among National Collegiate Athletic Association (NCAA) soccer players. Controversy remains regarding the effect of the surface type on the rate of ACL injury in soccer players, considering differences in sex, type of athletic exposure, and level of competition.Hypothesis:Natural grass surfaces would be associated with decreased ACL injury rate in NCAA soccer players. Sex, type of athletic exposure (match vs practice), and level of competition (Division I-III) would affect the relationship between playing surface and ACL injury rates.Study Design:Cohort study; Level of evidence, 3.Methods:Using the NCAA Injury Surveillance System (ISS) database, we calculated the incidence rate of ACL injury in men and women from 2004-2005 through 2013-2014 seasons. The incidence was normalized against athletic exposure (AE). Additional data collected were sex, athletic activity at time of injury (match vs practice), and level of competition (NCAA division) to stratify the analysis. Statistical comparisons were made by calculating incidence rate ratios (IRR). Statistical significance was set at an alpha of .05.Results:There were 30,831,779 weighted AEs during the study period. The overall injury rate was 1.12 ACL injuries per 10,000 AEs (95% CI, 1.08-1.16). Women comprised 57% of the match data (10,261 games) and 55% of practice data (26,664 practices). The overall injury rate was significantly higher on natural grass (1.16/10,000 AEs; 95% CI, 1.12-1.20) compared with artificial turf (0.92/10,000 AEs [95% CI, 0.84-1.01]; IRR, 1.26 [95% CI, 1.14-1.38]) (P < .0001). This relationship was demonstrated consistently across all subanalyses, including stratification by NCAA division and sex. The injury rate on natural grass (0.52/10,000 AEs; 95% CI, 1.11-1.26) was significantly greater than the injury incidence during practice on artificial turf (0.06/10,000 AEs; 95% CI, 0.043-0.096). Players were 8.67 times more likely to sustain an ACL injury during practice on natural grass compared with practice on artificial turf (95% CI, 5.43-12.13; P < .0001). No significant difference was found in injury rates between matches played on grass versus turf (IRR, 0.93; 95% CI, 0.84-1.03; P = .15).Conclusion:NCAA soccer players who practice on natural grass have increased risk of ACL injury compared with the risk of those practicing on an artificial surface, regardless of sex or NCAA division of play. No difference in risk of ACL injury between playing surfaces was detected during matches. Further research is necessary to examine the effect of multiple factors when evaluating the effect of the surface type on the risk of ACL injury in soccer players.

Identification of modifiable pre- and postnatal dietary and environmental exposures associated with owner-reported canine atopic dermatitis in Finland using a web-based questionnaire.

A cross-sectional hypothesis generating study was performed to investigate modifiable exposures such as whether feeding pattern (a non-processed meat based diet, NPMD, or an ultra-processed carbohydrate based diet, UPCD), certain environmental factors and their timing of exposure might be associated with the development of canine atopic dermatitis (CAD). Also, genetic and demographic factors were tested for associations with CAD. The data was collected from the validated internet-based DogRisk food frequency questionnaire in Finland. A total of 2236 dogs were eligible for the study (the owners reported 406 cases and 1830 controls). Our main interest was to analyze modifiable early risk factors of CAD, focusing on nutritional and environmental factors. We tested four early life periods; prenatal, neonatal, early postnatal and late postnatal periods. Twenty-two variables were tested for associations with CAD using logistic regression analysis. From the final models we identified novel dietary associations with CAD: the NPMD during the prenatal and early postnatal periods had a significant negative association with the incidence of CAD in adult dogs (age above 1 year). Oppositely, UPCD was associated with a significantly higher risk for CAD incidence. Other variables that were associated with a significantly lower risk for CAD were maternal deworming during pregnancy, sunlight exposure during early postnatal period, normal body condition score during the early postnatal period, the puppy being born within the same family that it would stay in, and spending time on a dirt or grass surface from 2 to 6 months. Also, the genetic factors regarding maternal history of CAD, allergy-prone breeds and more than 50% white-colored coat all showed a significant positive association with CAD incidence in agreement with previous findings. Although no causality can be established, feeding NPMD early in life seemed to be protective against CAD, while UPCD could be considered a risk factor. Prospective intervention studies are needed to establish the causal effects of the protective role of NPMD on prevalence of CAD during the fetal and early postnatal life.

Modelling of vibration and noise behaviour of embedded tram tracks using a wavenumber domain method

Tracks with rails embedded in a layer of rubber are commonly used for tramways. The vibration and sound radiation behaviour of these tracks differs from that of conventional railway tracks. This is studied here using coupled wavenumber finite element and boundary element models. A detailed analysis is carried out for an embedded rail with a narrow embedding material and comparisons are made with field measurements. The rail, embedding material and surrounding concrete are modelled with finite elements, whereas the support conditions due to the underlying ground are modelled with structural boundary elements coupled to the base of the track model. The sound radiation is calculated using a wavenumber acoustic boundary element model in which it is assumed that there is only one-way coupling with the structure. At low frequencies, vibration of the concrete slab also contributes to the noise radiation. Consequently, the radiated sound is increased compared with that produced by the rail alone at low frequencies but it is reduced above 300 Hz, where the rail and concrete vibrate out of phase with one another; at frequencies above 500 Hz the concrete has negligible effect. The track decay rate has a broad minimum between 500 and 1000 Hz; the noise radiation therefore has a peak in this important frequency region. However, the decay rate increases strongly above 1000 Hz due to the influence of the embedding material. The track considered has a grass in-fill between and outside the rails and allowing for the absorptive effect of the grass leads to a small reduction in the sound radiation. In addition, the attenuation effect of the fairings around the bogie region is estimated taking account of the absorptive effect of the grass surface. The embedded rail models are coupled with a model of a tram wheel and used to predict the rolling noise during the passage of a tram, showing good agreement with field measurements. Finally, various alternative embedded rail designs are compared, including different shapes of the embedding material and different rail profiles. Differences of up to 3 dB are found between the various designs.

Development of mobile robot for measuring distance using optical quadrature encoder

&lt;span&gt;This paper describes the design and development of a measuring tool using a mobile robot. At present, contractors are measuring distances using measuring tape which has few limitations. This includes using of another manpower or a marking flag. The Robot Measuring System is designed to measure distances at multiple conditions such as smooth and rough surface. An optical quadrature encoder is used as a sensor to measure the distances while a program is installed in Arduino Uno for reading and data collection. Graphical User Interface (GUI) was created using Android software so that the movement of the robot can be controlled using a smartphone within a Bluetooth range. An experiment was conducted to test the reliability in terms of accuracy and precision. The best accuracy and precision were obtained when the robot speed is at 90 cm/s on the plain tiles, 80 cm/s on the tar road and 90 cm/s on the grass surface. The robot speed needs to be adjusted accordingly based on the surfaces in order to get an accurate result. &lt;br /&gt; This paper proved that the robot measuring system was successfully designed, implemented and analyzed.&lt;/span&gt;

Analysis of Grand Slam Tennis Tournaments by Gender

The aim of this study is to analyze the variables determined in tournaments on different court surfaces by gender. In this research, official websites of 2019 Grand Slam tennis tournaments were used in the category of single men and single women as data collection tool. In the research, winning matches in the American Open and Australian Open played on hard surface (250 single men, 252 single women), the French Open played on clay surface (127 single men, 122 single women) and Wimbledon played on grass surface (127 single men, 126 single women) were analyzed. In these competitions, aces, double fault, win on 1st. serve, win on 2nd. serve, break points, unforced errors, winner, total points, fastest service and match duration were evaluated. SPSS 22.0 statistical software was used to evaluate the data and to find the calculated values. Since the data showed normal distribution, t test was used in independent groups and the level of significance was accepted as 0.05. When the variables taken into consideration were compared by gender, there was no statistically significant difference between men and women only in the double fault variable in the clay court (p> 0.05), whereas all other variables were significantly different in all courts (p <0.05). It has been determined that women's double fault, break points and unforced errors on hard and grass court, break points and unforced errors performance on clay court are better than man athletes. As a result, it can be said that the selected variables are affected by the gender factor on all court surfaces.

The Effect Of Playing Surface On Anterior Cruciate Ligament Injury In NCAA Soccer

Objectives: Previous orthopaedic literature has examined the effect of synthetic playing surfaces on the risk of anterior cruciate ligament (ACL) injury in athletes and produced varying and inconclusive results. The objective of this study was to examine the role of playing surface on the incidence and risk of ACL injury in collegiate soccer athletes. Methods: The NCAA Injury Surveillance Program (ISP) database was queried for ACL injuries for male and female soccer players from the 2004-05 through the 2013-14 seasons at all levels of competition. The number of athlete exposures (AEs), defined as 1 athlete participating in 1 practice or competition in which they were exposed to the possibility of athletic injury, were recorded for grass and synthetic playing surfaces. Both the reported injuries and exposures provided were weighted in order to represent the entire NCAA collegiate soccer population. Normalized ACL incidence rates were calculated as well as 95% confidence intervals (95%CI). Rate ratios comparing competition type amongst both competition and practice were calculated. Results: ACL injuries were more common on grass surfaces (1.16 per 10,000 AEs, 95%CI 1.12-1.20) than artificial turf (0.92 per 10,000 AEs, 95%CI 0.84-1.04). This difference was statistically significant (IRR 1.26, p&lt;0.0001), and driven primarily by the difference in injury incidence during practice. The injury incidence during practice on natural grass (1.18 per 10,000 AEs, 95% CI 1.11-1.26) was significantly greater than the injury incidence rate during practice on artificial turf (0.067 per 10,000 AEs, 95%CI 0.043-0.096). Players were 17.7 times more likely (95%CI 10.6678-27.2187, p&lt;0.0001) to sustain an ACL injury during practice on natural grass when compared to practice on artificial turf. However, there was no significant difference in injury incidence during matches (IRR 0.96, p=0.44), with matches on natural grass (3.35 per 10,000 AEs, 95% CI 3.21-3.51) equivalent to matches on artificial surfaces (3.49 per 10,000 AEs, 95%CI 3.18-3.81). When comparing exposure type, the injury rate was significantly greater during matches (3.38 per 10,000 AEs, 95% CI 3.25-3.52) compared to practices (0.82 per 10,000 AEs, 95%CI 0.77-0.88), with a 4.10-fold increase in ACL injury incidence during matches compared to practice (p&lt;0.0001). Conclusion: Between 2004 and 2014, NCAA soccer players experienced a greater number of ACL injuries on natural grass playing surfaces compared with artificial turf playing surfaces. This difference is driven by injuries during practice, where athletes were nearly 18 times more likely to suffer an ACL injury on grass versus artificial turf. While ACL injuries were more likely during matches compared to practices, no difference in incidence was noted between playing surfaces. Additional study is warranted investigating potential causes for this observed increased risk with soccer practice on grass fields.

Verification of radioecological models to the instrumental data of the specific activity &lt;sup&gt;131&lt;/sup&gt;I in a grass in Mazovia and Bohemia after the Chernobyl accident (from “Prague” and “Warsaw” scenarios of the IAEA project EMRAS

The analysis of instrumental data of “Prague” and “Warsaw” scenarios on the dynamics of 131I specific activities in the grass is carried out. Reconstruction of the 131I the specific activities dynamics in the grass in the Mazovia and Bohemia localities is performed in three models: direct calculation the input data of the “Prague” and “Warsaw” scenarios, homogeneous cloud, heterogeneous rain and heterogeneous cloudhomogeneousrain. The actual 137Cs fallout densities in the grass sampling sites in average more than 2.9 times for Prague and 2 times for Warsaw. Effective rain during the main fallout at the grass sampling sites, reconstructed on the model of a homogeneous cloud is 3–4 times more than at the nearest weather stations during this time. A realistic scenario of the input data leading to the optimal agreement of the calculated and instrumental data is revealed. It is shown that direct calculations and the homogeneous cloud model give almost identical results and lead to a significantly better agreement with the instrumental data than the an inhomogeneous cloud model. The calculated and instrumental data show a significant decrease in the 131I specific activity in the grass after the end of the main fallout due to its flushing from the grass surface by strong prolonged rain 13 and 19 days after the accident in Mazovia and 30 and 35 days in Bohemia. Uncertainties in the results of reconstruction of the dynamics of 131I and 137Cs activities in vegetation are estimated. The meangeometric values and standard mean-geometric deviations of the calculation/ 8instrumental data ratios are: 0.8–1.1 and 1.8–1.9 for grass.

Unghosting Bones: Resistant Play(s) versus the Legacy of Carlisle Indian Industrial School

Unghosting BonesResistant Play(s) versus the Legacy of Carlisle Indian Industrial School Jen Shook (bio) "Flesh can house no memory of bone. Only bone speaks memory of flesh." —Rebecca Schneider, "Archives: Performance Remains" "We talk about historical trauma… A hundred and thirty years later, this still has an impact on our youth. We're trying to make peace with those spirits and bring them home." —Russell Eagle Bear, Rosebud Sioux Historic Preservation Officer In N. Scott Momaday's The Moon in Two Windows, Luther Standing Bear, the first graduate of Carlisle Indian Industrial School, returns years later to catch a football game between Carlisle and the Army team. Moon closes as Luther and his son walk through the graves of Carlisle's cemetery, a resonant site for those who refuse to forget the genocidal legacy of the boarding school system launched at Carlisle, Pennsylvania. The young boy points to distant figures of a man and a child holding hands, swinging "round and round" (Momaday 177). Though the script does not identify them, the image echoes an earlier moment when Etahdleuh, an older member of Luther's transitional generation, swings round and round with Grass, the ghost of a girl who died on the train from the reservation to the school. The joyful yet haunting, lively yet dead, Grass and Etahdleuh surface as remains from Carlisle founder Richard Pratt's assimilationist mantra, "Kill the Indian, save the man." While the Pratt who Luther sees at the football game totters with age, throughout the earlier era portrayed in most of Moon Pratt organizes his school with vigor with Etahdleuh serving as his cultural translator. Moon, in other words, travels back [End Page 159] and forth through time, stitching connections for the audience between Carlisle's graves, Pratt's commands, and the students' transcultural negotiations. Grass's death troubles Pratt's orderly plan, and what to do with her remains gestures toward another ongoing Native and US negotiation: protection and repatriation of the dead. That football game that Luther watches features another historical Carlisle alumnus, Olympian Jim Thorpe. Like the students beneath the Carlisle gravestones, Thorpe's remains also lie in Pennsylvania, but his family has been fighting for their return to his native Oklahoma for over fifty years. This legal battle plays out in a fictionalized documentary in Suzan Shown Harjo and Mary Kathryn Nagle's play, My Father's Bones. Together, The Moon in Two Windows (2006), by N. Scott Momaday (Kiowa), and My Father's Bones (2013), by Suzan Shown Harjo (Cheyenne/Hodulgee Muscogee) and Mary Kathryn Nagle (Cherokee), resist the dismissal of anti-Native violence as a closed past event, calling to action both Native and non-Native audiences through embodied ghosts, cultural translation, empathy-modeling onstage audiences, and family/kinship interpellations. Both plays not only unghost the past in service of necessary and portable debate for present and future community health, they bring ghosts to life onstage in their activist memorializing of two specific issues: the generational loss perpetrated by the residential school system and the cultural genocide of looted human remains and sacred objects. By "unghost," I mean to make visible or acknowledge the presence of figures that have been obscured or ignored. To deal with ghost language in the landscape of Indigenous art carries a danger of reinscribing the erasure of Native peoples, the romantic obsession with their vanishment that fueled even so-called "Friends of the Indians" social movements. Yet un ghosting both attends to that erasure and amplifies the resilience, the survivability, of the peoples and cultures who remain and thrive despite centuries of genocide. While stage Indian ghosts haunted early US drama (and fiction and poetry and more) to perform an assuagement of settler guilt, the dead characters of Moon and Bones unsettle history and weave time to promote survivability.1 Unquiet memory in unburied bones circles like Grass and Etahdleuh in the Carlisle cemetery, unghosting hidden or ignored presences. Ghost characters might veer dangerously close to vanishment, the ongoing elegiac obsession [End Page 160] with "the last of the" that leads to convenient assumptions that Native peoples are extinct.2 Yet these stage ghosts must be played by actual actors, visibly...

Enzymatic sugar production from elephant grass and reed straw through pretreatments and hydrolysis with addition of thioredoxin-His-S

BackgroundThe bioconversion of lignocellulose to fermentable C5/C6-saccharides is composed of pretreatment and enzymatic hydrolysis. Lignin, as one of the main components, resists lignocellulose to be bio-digested. Alkali and organosolv treatments were reported to be able to delignify feedstocks and loose lignocellulose structure. In addition, the use of additives was an alternative way to block lignin and reduce the binding of cellulases to lignin during hydrolysis. However, the relatively high cost of these additives limits their commercial application.ResultsThis study explored the feasibility of using elephant grass (Pennisetum purpureum) and reed straw (Phragmites australis), both of which are important fibrous plants with high biomass, no-occupation of cultivated land, and soil phytoremediation, as feedstocks for bio-saccharification. Compared with typical agricultural residues, elephant grass and reed straw contained high contents of cellulose and hemicellulose. However, lignin droplets on the surface of elephant grass and the high lignin content in reed straw limited their hydrolysis performances. High hydrolysis yield was obtained for reed straw after organosolv and alkali pretreatments via increasing cellulose content and removing lignin. However, the hydrolysis of elephant grass was only enhanced by organosolv pretreatment. Further study showed that the addition of bovine serum albumin (BSA) or thioredoxin with His- and S-Tags (Trx-His-S) improved the hydrolysis of alkali-pretreated elephant grass. In particular, Trx-His-S was first used as an additive in lignocellulose saccharification. Its structural and catalytic properties were supposed to be beneficial for enzymatic hydrolysis.ConclusionsElephant grass and reed straw could be used as feedstocks for bioconversion. Organosolv and alkali pretreatments improved their enzymatic sugar production; however, the increase in hydrolysis yield of pretreated elephant grass was not as effective as that of reed straw. During the hydrolysis of alkali-pretreated elephant grass, Trx-His-S performed well as additive, and its structural and catalytic capability was beneficial for enzymatic hydrolysis.

Machine Learning Enables High-Throughput Phenotyping for Analyses of the Genetic Architecture of Bulliform Cell Patterning in Maize.

Bulliform cells comprise specialized cell types that develop on the adaxial (upper) surface of grass leaves, and are patterned to form linear rows along the proximodistal axis of the adult leaf blade. Bulliform cell patterning affects leaf angle and is presumed to function during leaf rolling, thereby reducing water loss during temperature extremes and drought. In this study, epidermal leaf impressions were collected from a genetically and anatomically diverse population of maize inbred lines. Subsequently, convolutional neural networks were employed to measure microscopic, bulliform cell-patterning phenotypes in high-throughput. A genome-wide association study, combined with RNAseq analyses of the bulliform cell ontogenic zone, identified candidate regulatory genes affecting bulliform cell column number and cell width. This study is the first to combine machine learning approaches, transcriptomics, and genomics to study bulliform cell patterning, and the first to utilize natural variation to investigate the genetic architecture of this microscopic trait. In addition, this study provides insight toward the improvement of macroscopic traits such as drought resistance and plant architecture in an agronomically important crop plant.

Reference Evapotranspiration Assessment Techniques for Estimating Crop Water Requirement

Water scarcity is a serious issue that has to be addressed in order to face the increasing water demands. Due to this issue, agricultural crops do not receive the required amount of water. So, it is necessary to have a proper technique to determine the water requirement for a particular crop. Evapotranspiration (ET), a process which is reliant on numerous climatic conditions, quantifies the loss of water from soil and crops through evaporation and transpiration processes respectively. Reference evapotranspiration ET is a concept of estimating ET from the reference surface which resembles an in-depth surface of green grass of stable height, actively growing, fully shading the surface with sufficient water. The amount of water required for a crop is thus determined by multiplying ETo with the crop coefficient (Kc) which depends on the growth stages and duration of a crop. So, evapotranspiration is considered to be one of the successful approaches to optimize the usage of water for crops. A literature survey is carried out on the popular methods of estimating ETo and their merits, demerits are discussed in this paper. Also, the impact of various climatic factors on ETo is presented. From the survey, it is known that ETo is estimated using conventional and non-conventional methods like Penman-Monteith, Blaney-Criddle, Hargreaves, ANN and WNN, regression and fuzzy logic. Humidity, temperature, wind speed, and solar radiation are the factors that have a major impact on estimating ETo. Generally, conventional methods are tedious since it requires experimental setups and more climatic data to determine ETo which are not available in many under developing countries. Thus, in this case, non-conventional methods are found to yield better results from the survey.

Environmental behaviour of radioactive particles: Transfer to animals

Field data on behaviour of artificial polydisperse radioactive silica particles in the components of the cattle food chain are presented. The model fused radioactive particles reproduced the spherical shape of particles in the local deposition during nuclear tests, including their specific gravity and polydispersity. It is shown that the composition of radioactive particles entering the body of animals differs from those initially deposited on the surface of pasture grass. The intake of particles into the body of animals decreased with increasing particle size. The intake for particles of 400–800 μm was about 10 times lower than that for fine particles sized 0–100 μm. It was found that the excretion rate of radioactive particles from the animal body also depends on particle size. The deposition of radioactive particles on the fundal surface of the wall of the ventral rumen sac and reticulum, as well as the long-term retention of radioactive particles of all sizes in the abomasum was noted. This can result in substantial damage in the GIT system, in particular, in these parts of the cattle digestive tract the focal ulcerative lesions of the mucous membrane can be formed by « hot » radioactive particles.

Repeated sprint ability (RSA) performance is not related to body height and body weight measurements among perak sukma 2018 male rugby players

Repeated sprint ability (RSA) is typically used for speed-endurance and agility-endurance training and assessment. RSA is preferred as it mimics actual performance during competition. RSA test involves straight sprint and quick turning movements. Thus, the aim of this study is to determine the relationship between height and body weight measurements on RSA performance, as height and weight may influence the mechanical properties of it. Ten male rugby players (body weight 72.99 ± 14.29 kg, height 169 ± 5.55 cm) selected for Perak SUKMA 2018 team were assessed during centralized training ~9 months prior to their competition. Body weight and height were measured using standard laboratory weight and height scales prior to the RSA test. RSA were hand-timed for 5 repetitions x 2 sets x 60 seconds rest in between repetitions x 5 minutes rest in-between set. The sprints were performed in the evenings, on grass surface with participants wearing full playing attire. Standardized pre-game warm-up and cooling down were performed. Data recorded was analyzed statistically using a t-test comparison for set one versus set two performances. Pearson correlation coefficient was used to analyze the relationship between anthropometric measures and the RSA test. RSA performance has a negative correlation with the athletes’ height (r= -0.233 set 1, r = -0.435 set 2) and body weight (r= -0.556 set 1, r= -0.629 set 2). RSA performance was significantly different between set 1 and set 2 (p=0.001), with set 1 performance better than set 2. Body height and body weight did not influence RSA performance. Athletes involved did not have adequate speed-agility-endurance needed. In practical, selecting athletes based on their body height and body weight with the assumption that taller and heavier athletes may perform better may not be suitable for this kind of sport. On the other hand, using RSA to test and develop the speed-agility-endurance ability for rugby players is suggested.&#x0D;

Evapotranspiration and crop coefficient patterns of an apple orchard in a sub-humid environment

Increasing water use efficiency is one of the main challenges of sustainable fruit tree production. From 2013 to 2015 we measured actual evapotranspiration (ETa) using eddy covariance in a well-irrigated apple orchard located in in South Tyrol (Italy), a sub-humid environment. We assessed the experimental crop coefficient (Kcexp) and analyzed the dependency of Kc on specific environmental variables at a daily time scale. Kcexp values changed throughout the season following a bell-shaped trend and were generally lower than the FAO tabular values corrected for local climatic conditions. In the mid-season phase, when LAI and tabular Kc are supposed to be constant, the average experimental Kc (Kc¯exp) was 1.01, 86% of the Kc value reported by FAO (1.18). Mid-season Kc residuals (Kcexp - Kc¯exp) were positively correlated with daily vapor pressure deficit (VPD) (ρ = 0.45), suggesting that the daily Kc variability observed is due, at least in part, to changes in the evaporative demands of the atmosphere. We explain these results by considering the relatively humid environment, the high water availability and the fact that leaves on apple trees are more tightly coupled to the atmosphere with respect to a smoother grass surface.

Injury Surveillance in Major League Soccer: A 4-Year Comparison of Injury on Natural Grass Versus Artificial Turf Field

Background: Artificial playing surfaces are becoming more common due to decreased cost of maintenance and increased field usability across different environmental conditions. The Fédération Internationale de Football Association (FIFA) has approved newer generation artificial turf for soccer competition at the elite level, but many elite-level athletes prefer to play on natural grass surfaces due to a perceived increase in injury rate, discomfort, and fatigability on artificial turf. Hypothesis: Injury rates and rates of individually categorized types of injury experienced on artificial turf are noninferior to rates of injury on the standard comparator, natural grass, in elite-level Major League Soccer athletes. Study Design: Cohort study; Level of evidence, 2. Methods: Over the course of 4 Major League Soccer seasons (2013-2016), athlete injury data were recorded electronically. Injury data recorded in matches between 2 Major League Soccer teams were then analyzed. Playing surface was known for each venue, and all artificial turf surfaces were rated as 2-star according to FIFA criteria. Incidence rate ratios (Artificial Turf ÷ Natural Grass) were calculated with a 95% CI (α = .05) for both overall injury incidence and individual injury subgroups. A noninferiority margin (δ) of 0.15 was used to determine noninferiority of injury incidence rates. Results: A total of 2174 in-game injuries were recorded during the study period, with 1.54 injuries per game on artificial turf and 1.49 injuries per game on natural grass (incidence rate ratio, 1.033; 95% CI, 0.937-1.139). Within injury subgroups, overall ankle injury, Achilles injury, and ankle fracture were found to have a statistically higher incidence on artificial turf. Artificial turf was found to be noninferior to natural grass for overall foot injury and forefoot injury. No statistically significant differences were found in knee injuries between the 2 surfaces. Conclusion: The overall rate of injury on artificial turf was noninferior to that on natural grass. Within individual injury categories, a higher rate of ankle injury was found on artificial turf. No other injury subgroup demonstrated statistically significant differences between surfaces. Clinical Relevance: FIFA 2-star rated artificial turf is a viable alternative to natural grass in elite-level soccer competition. Innovative research methods for comparing artificial turf versus natural grass may elucidate relative advantages with respect to player safety.

The influence of observed and modelled net longwave radiation on the rate of estimated potential evapotranspiration

Abstract Longwave radiation, as part of the radiation balance, is one of the factors needed to estimate potential evapotranspiration (PET). Since the longwave radiation balance is rarely measured, many computational methods have been designed. In this study, we report on the difference between the observed longwave radiation balance and modelling results obtained using the two main procedures outlined in FAO24 (relying on the measured sunshine duration) and FAO56 (based on the measured solar radiation) manuals. The performance of these equations was evaluated in the April–October period over eight years at the Liz experimental catchment and grass surface in the Bohemian Forest (Czech Republic). The coefficients of both methods, which describe the influence of cloudiness factor and atmospheric emissivity of the air, were calibrated. The Penman-Monteith method was used to calculate the PET. The use of default coefficient values gave errors of 40–100 mm (FAO56) and 0–20 mm (FAO24) for the seasonal PET estimates (the PET was usually overestimated). Parameter calibration decreased the FAO56 error to less than 20 mm per season (FAO24 remained unaffected by the calibration). The FAO56 approach with calibrated coefficients proved to be more suitable for estimation of the longwave radiation balance.

Dwarf eelgrass (Zostera noltii) leaf fatty acid profile during a natural restoration process: Physiological and ecological implications

Abstract Seagrass beds are among the most relevant ecosystem engineers, providing essential ecosystem services for the surrounding coastal communities. Alongside, these ecosystems are among the most threaten in the world, and thus several restoration projects have been developed in the past years. Seagrasses are important sources of essential fatty acids (FA) for animals, which are unable to synthetize them. During the seagrass growth and photochemical maturation, there is a membrane remodelling, where some fatty acids are synthetized. When analysing the FA changes at different development stages, one of the first noticeable changes is the increase in C16:1t (trans-hexadecenoic acid), associated to an increase in the chloroplast membrane fluidity, essential for the efficient energy transduction processes to occur in the thylakoids. Also, interesting to observe are the high levels of omega-3 and -6 (30–43% and 18–31% of total fatty acid content, respectively) present in this seagrass, reinforcing the nutritional value of this species as source of essential fatty acids for the primary consumers. Additionally, it is possible to observe that in the more mature plants there is a high leaf concentration of C18:3. Recent reports suggest that C18:3 can act as a direct scavenger of reactive oxygen species (ROS), indicating a lower stress level, as suggested by the higher photochemical efficiency previously observed. Moreover, it is also interesting to observe that total long-chain polyunsaturated fatty acids (LC-PUFAs) content show a significant increase with the biomass development. These LC-PUFAs are not produced by higher plants and their production in animals occurs at low rates, suggesting they may have as origin the microalgae in the grass surface, adding another important ecosystem service to these prairies, as support for microalgae development and carriers of LC-PUFAs into the food web. This membrane remodelling appears to be on the basis of the photochemical maturation of these seagrasses observed in previous studies and can be used as potential and efficient tool to monitor the development stage of the prairies and its physiological status in future restoration processes. Moreover, it becomes evident that highly developed seagrass beds are crucial food source providers in terms of essential fatty acids to the estuarine heterotrophic life.

Barefoot Running As A Treatment For Plantar Fasciitis In The Runner: A Case Series

PURPOSE: Plantar fasciitis is the most common running related injury associated with the foot and represents ~8% of all running injuries. The median recovery time for plantar fasciitis is ~5-months. Following the failure of conservative management for a female runner with plantar fasciitis, we trialled an alternate day treatment strategy of barefoot running on a grass surface (10 - 15 minutes). This approach was successful and was published as a medical case report. This abstract aims to describe the results of an emerging case series (n=4) using a similar approach. METHODS: Four amateur runners (2 male, 2 female, age 27-45 years) were diagnosed as having plantar fasciitis. In all cases, the failure of conservative management led to them being prescribed a barefoot running intervention on grass. Patients were instructed to complete 10-15 minutes (dependent on pain tolerance) of barefoot running every second day and record pain scores using the visual analog scale (VAS) every morning. RESULTS: Mean pain intensity (scored out of 10) at the beginning of the intervention was 5.4 ± 1.5 (range 3.5 - 7). After 6 sessions of barefoot running, mean pain intensity had reduced to 2.0 ± 1.6 (range 2.0 - 4.0). All patients demonstrated an improvement in pain intensity after 4-sessions. Three patients sustained this improvement up to session 6 and one patient reverted to their original pain score (4). The two female patients demonstrated an immediate and sustained reduction in pain. The two male patients initially remained unchanged or increased pain intensity before improving. DISCUSSION: The results of this emerging case series suggest that this intervention is at least well tolerated in runners with chronic plantar fasciitis. The fact that the intervention contains the activity known to worsen symptoms may suggest this approach has some promise. However, it is not possible to infer cause and effect from a case series and the improvements shown in this series may be due to other factors such as the passage of time or a reduction in fear avoidance behaviour.

Comparing the transpirational and shading effects of two contrasting urban tree species

Urban trees are getting increasing attention as a tool to mitigate urban heat island effects. A more functional and quantitative view of transpirational and shading effect, particularly the magnitude of both surface and air cooling potential can further strengthen motivations for urban tree planting. We investigated the transpirational and the surface cooling potential of two contrasting tree species in Munich, Germany: ring porous Robinia pseudoacacia L. and diffuse porous Tilia cordata Mill. Throughout the summer 2016 we monitored meteorological and edaphic variables and tree sap-flow along with the air temperature within and outside tree shade at different heights. With 30% higher leaf area index (LAI), double sap-flux density and sapwood area, T. cordata trees showed three times higher transpiration compared to the R. pseudoacacia. Consequently, T. cordata trees showed higher within canopy air cooling effect. Surface cooling (∆Tshade) were higher under the denser canopies of T. cordata compared to R. pseudoacacia for asphalt surfaces but ∆Tshade for grass surfaces were not significantly different under the canopies of two species. Linear regression indicated a decrease in grass surface temperature of 3 °C with every unit of LAI but for asphalt, the reduction in surface temperature was about 6 °C. Additionally, higher water using efficiencies of R. pseudoacacia coupled with higher soil moisture and radiation probably increased the grass evapotranspiration and subsequently showed positive relationship with the near ground air cooling. Therefore, species with higher canopy density might be preferred over asphalt surfaces but low water using species with lower canopy density could be chosen over grass surfaces.

Running biomechanics as measured by wearable sensors: effects of speed and surface

ABSTRACT Running biomechanics research has traditionally occurred in the laboratory, but with the advent of wearable sensors measurement of running biomechanics may shift outside the laboratory. The purpose was to determine if RunScribe™ wearable sensors could detect differences in kinematic, kinetic and spatiotemporal measures during runs at two speeds and on two different surfaces. Fifteen recreational runners (7 males, 8 females; age = 20.0 ± 3.1 years) participated. While wearing sensors on the heels of their shoes, participants completed four 1600 m runs on both track and grass surfaces. On each surface, the first 1600 m was at a self-selected slow speed followed by the second 1600 m at a self-selected fast pace. The sensors quantified several kinetic, kinematic and spatiotemporal measures. Repeated measures ANOVAs compared the effects of surface and speed. The spatiotemporal measures of stride length, cycle time and contact time were predictably affected by increased running speed and increased surface stiffness, as were the kinematic and kinetic measurements of maximum pronation velocity, maximum pronation excursion, impact g, and braking g (p < 0.050). The RunScribe™ sensors identified expected changes in running biomechanics measures at different speeds and on varying surfaces.