The Grassholme Channels

The design and construction of four experimental channels at Grassholme reservoir in Teesdale, County Durham (UK) are briefly described. The problem of obtaining valid replication between channels is examined using published data obtained for previous experiments in the channels. It is concluded that replication may be obtained by careful experimental design. The limitations of the existing configuration of pipework and channel design are discussed and solutions suggested. Finally a list of the main components of the channels and suppliers is appended. Alternative materials and suppliers could well be found for most items. (PDF contains 23 pages

Analysis of repeated high-intensity running performance in professional soccer

The aims of this study conducted in a professional soccer team were two-fold: to characterise repeated high-intensity movement activity profiles in official match-play; b) to inform and verify the construct validity of tests commonly used to determine repeated-sprint ability in soccer by investigating the relationship between the results from a test of repeated-sprint ability and repeated high-intensity performance in competition. High-intensity running performance (movement at velocities >19.8 km/h for a minimum of 1-s duration) in 20 players was measured using computerised time motion analysis. Performance in 80 French League 1 matches was analysed. In addition, 12 out of the 20 players performed a repeated-sprint test on a non-motorized treadmill consisting of 6 consecutive 6s sprints separated by 20s passive recovery intervals. In all players, the majority of consecutive high-intensity actions in competition were performed after recovery durations ≥61s, recovery activity separating these efforts was generally active in nature with the major part of this spent walking, and players performed 1.1±1.1 repeated high-intensity bouts (a minimum of 3 consecutive high-intensity with a mean recovery time ≤20s separating efforts) per game. Players reporting lowest performance decrements in the repeated-sprint ability test performed more high-intensity actions interspersed by short recovery times (≤20s, p<0.01 and ≤30s, p<0.05) compared to those with higher decrements. Across positional roles, central-midfielders performed a greater number of high-intensity actions separated by short recovery times (≤20s) and spent a larger proportion of time running at higher intensities during recovery periods while fullbacks performed the most repeated high-intensity bouts (statistical differences across positional roles from p<0.05 to p<0.001). These findings have implications for repeated high-intensity testing and physical conditioning regimens

Improving the Design of Slash Roads Used to Reduce Soil Disturbance During Mechanised Harvesting of Coniferous Forest Plantations in the UK

During mechanised forest harvesting, extraction routes may be armoured with a dense carpet of logging residues (slash roads) to reduce soil disturbance associated with heavy machinery. However, guidelines regarding the design of slash roads remain largely qualitative, and their efficacy as a means of ground protection uncertain. Trials were undertaken in north-east England and south-west Scotland to identify the main causes of slash road failure during repeated trafficking. Failure of the slash roads was defined as (a) deflection of logging residues and exposure of the ground surface to harvesting machinery or (b) mixing of logging residues with surface soils. The frequency of slash road failure was directly linked to terrain factors (soil water content, the presence of rocks, tree stumps, furrows and drain channels, or slope). In addition, failure was linked to the design of the slash roads where large diameter logging residues were readily deflected, or at junctions and turning points where 'shearing' of the slash road took place. A simple means of assessing the potential for slash road failure is presented based on terrain characteristics. These guidelines allow harvesting staff to locate extraction routes in order to maximise the structural longevity of the slash road, whilst reducing down-time associated with their repair. In addition, and where standard yield tables apply, a means of predicting the volume of logging residues available at any site is demonstrated, and the implications of this for effective slash road construction are discussed

Interpreting physical performance in professional soccer match-play: Should we be more pragmatic in our approach?

Academic and practitioner interest in the physical performance of male professional soccer players in the competition setting determined via time-motion analyses has grown substantially over the last four decades leading to a substantial body of published research and aiding development of a more systematic evidence-based framework for physical conditioning. Findings have forcibly shaped contemporary opinions in the sport with researchers and practitioners frequently emphasising the important role that physical performance plays in match outcomes. Time-motion analyses have also influenced practice as player conditioning programmes can be tailored according to the different physical demands identified across individual playing positions. Yet despite a more systematic approach to physical conditioning, data indicate that even at the very highest standards of competition, the contemporary player is still susceptible to transient and end-game fatigue. Over the course of this article, the author suggests that a more pragmatic approach to interpreting the current body of time-motion analysis data and its application in the practical setting is nevertheless required. Examples of this are addressed using findings in the literature to examine: a) the association between competitive physical performance and ‘success’ in professional soccer, b) current approaches to interpreting differences in time-motion analysis data across playing positions and, c) whether data can realistically be used to demonstrate the occurrence of fatigue in match-play. Gaps in the current literature and directions for future research are also identified

The impact of inter‐flood duration on non‐cohesive sediment bed stability

© 2019 John Wiley & Sons, Ltd. Limited field and flume data suggests that both uniform and graded beds appear to progressively stabilize when subjected to inter-flood flows as characterized by the absence of active bedload transport. Previous work has shown that the degree of bed stabilization scales with duration of inter-flood flow, however, the sensitivity of this response to bed surface grain size distribution has not been explored. This article presents the first detailed comparison of the dependence of graded bed stability on inter-flood flow duration. Sixty discrete experiments, including repetitions, were undertaken using three grain size distributions of identical D50 (4.8 mm); near-uniform (σg = 1.13), unimodal (σg = 1.63) and bimodal (σg = 2.08). Each bed was conditioned for between 0 (benchmark) and 960 minutes by an antecedent shear stress below the entrainment threshold of the bed (τ*c50). The degree of bed stabilization was determined by measuring changes to critical entrainment thresholds and bedload flux characteristics. Results show that (i) increasing inter-flood duration from 0 to 960 minutes increases the average threshold shear stress of the D50 by up to 18%; (ii) bedload transport rates were reduced by up to 90% as inter-flood duration increased from 0 to 960 minutes; (iii) the rate of response to changes in inter-flood duration in both critical shear stress and bedload transport rate is non-linear and is inversely proportional to antecedent duration; (iv) there is a grade dependent response to changes in critical shear stress where the magnitude of response in uniform beds is up to twice that of the graded beds; and (v) there is a grade dependent response to changes in bedload transport rate where the bimodal bed is most responsive in terms of the magnitude of change. These advances underpin the development of more accurate predictions of both entrainment thresholds and bedload flux timing and magnitude, as well as having implications for the management of environmental flow design. © 2019 John Wiley & Sons, Ltd. © 2019 John Wiley & Sons, Ltd

Ice-buttressing-controlled rock slope failure on a cirque headwall, Lake District, UK

Rock slope failures in the Lake District, UK, have been associated with deglacial processes after the Last Glacial Maximum, but the controls and timing of the failures remain poorly known. A cirque headwall failure was investigated to determine failure mechanisms and timing. The translated wedge of rock is thin and lies on a steep failure plane, yet the friable strata were not disrupted by downslope movement. Fault lines and a failure surface, defining the wedge, were used as input to a numerical model of rock wedge stability. Various failure scenarios indicated that the slope was unstable and would have failed catastrophically if not supported by glacial ice in the base of the cirque. The amount of ice required to buttress the slope is insubstantial, indicating likely failure during the thinning of the cirque glacier. We propose that, as the ice thinned, the wedge was lowered slowly down the cirque headwall, gradually exposing the failure plane. A cosmogenic 10Be surface exposure age of 18.0±1.2 ka from the outer surface of the wedge indicates Late Devensian de-icing of the backwall of the cirque, with a second exposure age from the upper portion of the failure plane yielding 12.0±0.8 ka. The 18.0±1.2 ka date is consistent with a small buttressing ice mass being present in the cirque at the time of regional deglaciation. The exposure age of 12.0±0.8 ka represents a minimum age, as the highly fractured surface of the failure plane has experienced post-failure mass-wasting. Considering the chronology, it appears unlikely that the cirque was reoccupied by a substantial ice mass during the Younger Dryas stadial.</p

Last ice-dammed lake in the Kuray basin, Russian Altai: New results from multidisciplinary research

Results from geomorphological, sedimentological and geochronological analyses, together with micropaleontological and mineralogical characteristics of lacustrine deposits in five locations within the Kuray intermountain depression, southeast Altai, mountains of south Siberia, support the thesis of repeated formations of ice-dammed lakes during MIS-2 and their draining by high energy floods. Our data suggest that the timing of one of the last cataclysmic draining events in the area can be estimated by an Optically-Stimulated Luminescence (OSL) age of 19.0 ± 1.1 ka for a sandy layer at the top of the diluvial (i.e. large flood) deposit, revealed in a sedimentary sequence of the 1570 m a.s.l. strandline – one of the lowest preserved strandlines in the western part of the basin. New OSL and radiocarbon ages, augmenting previously published dates, indicate that the last lake to occupy the Kuray depression occurred around 19–16 ka with a depth of at least 170 m in the central part of the basin and to a depth of no less than 220 m near the glacier dam. Lacustrine deposits are represented by two horizons of sandy clays separated by interlayers of mixed-size sands. The mineralogical data, supported by analysis of sedimentological and micropaleontological records, indicate accumulation of a lower lacustrine horizon in a deeper reservoir. Finding of Leucocythere sp.1, Leucocythere sp.2, and Leucocythere dorsotuberosa ostracod species in lacustrine deposits characterizes these reservoirs as periglacial freshwater cold and deep lakes. The presence of well-crystallized mica and chlorite in lacustrine silts and clays from the lower lacustrine horizon indicates cold, dry conditions at the time of their formation, as well as a predominance of physical weathering of rocks within the denudation area. After an abrupt dropping of the lake level around 16 ka, determined from OSL dating, the lake never recovered its former depth. The available radiocarbon ages for organic material in subaerial deposits within the study area and the new OSL ages suggest that the last ice-dammed lake in the Kuray basin was drained between ~16.7 and 9.9 ka. The presence of this lake might explain the absence of late Paleolithic surface finds within the basin that remained generally unsuitable for human habitation until its final drying. The last outburst flood passed along the Chuya and Katun river valleys, which had been already carved by older cataclysmic floods, but did not significantly affect the topography downstream of the Kuray-Chuya intermountain depressions. We numerically simulated the draining of a palaeolake in the Kuray basin with the water level 1650 m a.s.l. (maximal depth about 220 m near the dam) with different scenarios of breaching the ice dam. In contrast to a relatively gradual breach of the ice dam due to thermal erosion, an instantaneous dam break due to structural failure can cause an outburst flood with a peak discharge of around 2 × 106 m3 s−1. The high speeds of the water flow, 1.9–5.6 m s−1, with the maximum Froude numbers of 0.06–0.22, and peak Shields values of 0.03–0.25 indicate competence to mobilize gravel. Generally, the simulated flow remained subcritical, suggesting that bedforms developed under supercritical flows, such as antidunes, could not have developed, although the development of dunes cannot be precluded. Our data also contribute to the issue of correlating the low lake strandlines in the Kuray basin with the landforms associated with cataclysmic outburst floods.The study was supported by State Assignment of IGM SB RAS and partly funded by Russian Foundation for Basic Researches (grant 18-05-00998). We also benefited from the funds of the projects EX-AQUA (1623P) “Palaeohydrological Extreme Events - evidence and archives”, sustained by INQUA TERPRO. The flood modelling contribution by Bohorquez was supported by the Spanish Ministry of Science, Innovation and Universities (MICINN/FEDER, UE) under Grant SEDRETO CGL2015-70736-R

What is the impact of physical effort on the diagnosis of concussion?

Objective: Sport-related concussion commonly occurs in contact sports such as rugby. To date, diagnosis is based on the realization of clinical tests conducted pitch-side. Yet, the potential effect of prior physical effort on the results of these tests remains poorly understood. The purpose of this study was to determine whether preceding physical effort can influence the outcome of concussion assessments. Design: Prospective observational study. Setting: University Medicine Center Patients: A cohort of 40 subjects (20 rugby players and 20 athletes from a range of sports). Intervention: A concussion assessment was performed immediately following physical activity. Following a period of 6 months and under the same experimental conditions, the same cohort performed the same tests in resting conditions. Main outcome measure: Results of concussion tests. Results: In both cohorts, the comparison for post-exercise and rest assessments demonstrated a most likely moderate-to-very large increase in the number of symptoms, severity of symptoms and BESS score. In the rugby cohort, scores for concentration, delayed memory and SAC, likely-to-most likely decreased following completion of physical activity compared to baseline values. The between-cohort comparison showed a greater impact post-exercise in the rugby players for delayed recall (0.73±0.61, 93/7/1) and SAC score (0.75±0.41, 98/2/0). Conclusion: Physical activity altered the results of concussion diagnostic tests in athletes from a range of sports and notably in rugby players. Therefore, physical efforts prior to the concussion incident should be accounted for during pitch-side assessments and particularly during rugby competition and training

Luminescence Analyses of Samples from Thailand and Laos

Prior investigation of cover sands in Thailand and Vietnam identified two distinct materials present; material containing high sensitivity quartz with robust SAR-OSL luminescence ages &lt;35ka, and material containing lower sensitivity quartz with OSL signals in excess of the ~50ka saturation limit of the SAR method. Thermal transfer methods were developed to extend the range of equivalent dose determination for these older materials. In the work reported here, additional samples of older materials from three sites have been analysed to extend the extent of these observations. An additional set of profile samples (SUTL3002) and a dating sample (SUTL3003) were collected below the previous samples at Huai Om, Thailand. Laboratory profile measurements give similar sensitivities and apparent doses for quartz grains from the gravel layer to the earlier analyses from the sands immediately above these, with the sandy layer (associated with tektites) and weathered basement samples yielding quartz with even lower sensitivity. The tube sample from immediately above the weathered basement gives an age of 120 ± 10 ka, slightly older than the sample previously measured immediately above the gravel layer (95 ± 15 ka). A sample from the granule layer at Pakse, Laos (SUTL3004) gives an age of 150 ± 25 ka. A breccia sample from Tad Huakhon, Laos, (SUTL3005) taken from a layer between the basement and a basalt layer gives luminescence sensitivities two orders of magnitude higher than the lower sand and granule layer samples, potentially a result of heating from the lava flow above, and gives an age of 80 ± 20 ka

A high-density Diversity Arrays Technology (DArT) microarray for genome-wide genotyping in Eucalyptus

<p>Abstract</p> <p>Background</p> <p>A number of molecular marker technologies have allowed important advances in the understanding of the genetics and evolution of <it>Eucalyptus</it>, a genus that includes over 700 species, some of which are used worldwide in plantation forestry. Nevertheless, the average marker density achieved with current technologies remains at the level of a few hundred markers per population. Furthermore, the transferability of markers produced with most existing technology across species and pedigrees is usually very limited. High throughput, combined with wide genome coverage and high transferability are necessary to increase the resolution, speed and utility of molecular marker technology in eucalypts. We report the development of a high-density DArT genome profiling resource and demonstrate its potential for genome-wide diversity analysis and linkage mapping in several species of <it>Eucalyptus</it>.</p> <p>Findings</p> <p>After testing several genome complexity reduction methods we identified the <it>Pst</it>I/<it>Taq</it>I method as the most effective for <it>Eucalyptus </it>and developed 18 genomic libraries from <it>Pst</it>I/<it>Taq</it>I representations of 64 different <it>Eucalyptus </it>species. A total of 23,808 cloned DNA fragments were screened and 13,300 (56%) were found to be polymorphic among 284 individuals. After a redundancy analysis, 6,528 markers were selected for the operational array and these were supplemented with 1,152 additional clones taken from a library made from the <it>E. grandis </it>tree whose genome has been sequenced. Performance validation for diversity studies revealed 4,752 polymorphic markers among 174 individuals. Additionally, 5,013 markers showed segregation when screened using six inter-specific mapping pedigrees, with an average of 2,211 polymorphic markers per pedigree and a minimum of 859 polymorphic markers that were shared between any two pedigrees.</p> <p>Conclusions</p> <p>This operational DArT array will deliver 1,000-2,000 polymorphic markers for linkage mapping in most eucalypt pedigrees and thus provide high genome coverage. This array will also provide a high-throughput platform for population genetics and phylogenetics in <it>Eucalyptus</it>. The transferability of DArT across species and pedigrees is particularly valuable for a large genus such as <it>Eucalyptus </it>and will facilitate the transfer of information between different studies. Furthermore, the DArT marker array will provide a high-resolution link between phenotypes in populations and the <it>Eucalyptus </it>reference genome, which will soon be completed.</p