The relationships between rugby players’ tackle training attitudes and behaviour and their match tackle attitudes and behaviour

Background The tackle event in rugby is a technical and physical contest between opposing players. A player's ability to tolerate and contest during a tackle is a prerequisite for safe participation and success in rugby. Little is known about the relationship between tackle training and tackling in matches in rugby union. Therefore, we investigated the relationships between players’ training attitudes and behaviour and their match attitudes and behaviour for tackling in rugby union. Method A questionnaire was designed to assess attitude (importance) and behaviours (frequency and quantity) among junior (under 19) players on a 5-point Likert Scale. Questionnaires were handed out to 220 players (10 schools) at a tournament and 75% (9 schools, n=164) were returned for analysis. Associations between training attitudes and behaviours were tested using the χ2 test, Cramer's V and τ-b. Results The more time spent on emphasising proper technique to prevent injuries in training, the more important players rated ‘own safety’ (τ-b=0.21, moderate, z=3.1, p<0.01), ‘going for the ball only’ (τ-b=0.27, moderate, z=4.6, p<0.001) and ‘staying on feet’ (τ-b=0.23, moderate, z=3.6, p<0.001) in match play. The more time spent on emphasising proper technique to improve performance in training, the more important players rated actions ‘going for ball only’ (τ-b=0.23, moderate, z=3.7, p<0.001) and ‘preventing the ball carrier from retaining position’ (τ-b=0.20, moderate, z=3.1, p<0.01) in match play. Conclusions This is the first study to report on the relationships between players’ training attitudes and behaviour and their match attitudes and behaviours for tackling in rugby union. The importance of tackle training to prevent injury, and the amount of time spent on technique to prevent injuries, was associated with behaviours that reduce the risk of injury in matches

The development of post-processing algorithm for the ultrasonic evaluation by the application of automated robotic testing systems

The implementation of automated testing systems based on six degrees of freedom (DOF) robotic manipulators is the actual trend in ultrasonic testing equipment development. Such systems are able to provide a fast ultrasonic evaluation with the respect of the surface of the testing object. In this work, the post-processing algorithm based on Synthetic Aperture Focusing Technique (SAFT) is suggested. Such algorithm allows presenting the results in the form of high-resolution imagery of the internal structure of testing objects. The suggested algorithm is applicable in the case of the utilization of automated testing systems based on six DOF robotic manipulators and takes into account all the features conditioned by such equipment application. Performance of the suggested algorithm was tested experimentally

Küçük bir devr-i âlem

H. A.'nın Çocuklara Rehber'de tefrika edilen Küçük Bir Devr-i Âlem adlı roman

Project of motion capture system based on free layout of sensors on the modeled object

The article presents the review of motion capture systems based on different physical principles and used in different areas of human activity. There is a description of cheap system that can be used instead of foreign analogs. It is based on 9-axis motion capture devices and could allow to place these devices on different kind of objects

Uncertainties in VS profiles from geophysical tests and their influence on seismic ground response analyses: results from the Interpacific blind test

The InterPACIFIC project is aimed at the assessment of the reliability of different geophysical methods (both invasive and non-invasive) for the estimation of shear wave velocity profiles. Blind tests have been performed in three different subsoil conditions. The observed variability in the results provided by several operators gives a representation of the uncertainties that has to be expected in site characterization. The implications of these uncertainties on ground response analyses are considered in the present paper

Large-scale sedimentation on the glacier-influenced polar North Atlantic Margins: Long-range side-scan sonar evidence

Long-range side-scan sonar (GLORIA) imagery of over 600,000 km² of the Polar North Atlantic provides a large-scale view of sedimentation patterns on this glacier-influenced continental margin. High-latitude margins are influenced strongly by glacial history and ice dynamics and, linked to this, the rate of sediment supply. Extensive glacial fans (up to 350,000 km³) were built up from stacked series of large debris flows transferring sediment down the continental slope. The fans were linked with high debris inputs from Quaternary glaciers at the mouths of cross-shelf troughs and deep fjords. Where ice was slower-moving, but still extended to the shelf break, large-scale slide deposits are observed. Where ice failed to cross the continental shelf during full glacials, the continental slope was sediment starved and submarine channels and smaller slides developed. A simple model for large-scale sedimentation on the glaciated continental margins of the Polar North Atlantic is presented

A topological characterization of modulo-p arguments and implications for necklace splitting

The classes PPA-p have attracted attention lately, because they are the main candidates for capturing the complexity of Necklace Splitting with p thieves, for prime p. However, these classes were not known to have complete problems of a topological nature, which impedes any progress towards settling the complexity of the Necklace Splitting problem. On the contrary, topological problems have been pivotal in obtaining completeness results for PPAD and PPA, such as the PPAD-completeness of finding a Nash equilibrium [18, 15] and the PPA-completeness of Necklace Splitting with 2 thieves [24]. In this paper, we provide the first topological characterization of the classes PPA-p. First, we show that the computational problem associated with a simple generalization of Tucker's Lemma, termed p-polygon-Tucker, as well as the associated Borsuk-Ulam-type theorem, p-polygon-Borsuk-Ulam, are PPA-p-complete. Then, we show that the computational version of the well-known BSS Theorem [8], as well as the associated BSS-Tucker problem are PPA-p-complete. Finally, using a different generalization of Tucker's Lemma (termed Zp-star-Tucker), which we prove to be PPA-p-complete, we prove that p-thief Necklace Splitting is in PPA-p. This latter result gives a new combinatorial proof for the Necklace Splitting theorem, the only proof of this nature other than that of Meunier [42]. All of our containment results are obtained through a new combinatorial proof for Zp-versions of Tucker's lemma that is a natural generalization of the standard combinatorial proof of Tucker's lemma by Freund and Todd [27]. We believe that this new proof technique is of independent interest

Do contaminants originating from state-of-the-art treated wastewater impact the ecological quality of surface waters?

Since the 1980s, advances in wastewater treatment technology have led to considerably improved surface water quality in the urban areas of many high income countries. However, trace concentrations of organic wastewater-associated contaminants may still pose a key environmental hazard impairing the ecological quality of surface waters. To identify key impact factors, we analyzed the effects of a wide range of anthropogenic and environmental variables on the aquatic macroinvertebrate community. We assessed ecological water quality at 26 sampling sites in four urban German lowland river systems with a 0–100% load of state-of-the-art biological activated sludge treated wastewater. The chemical analysis suite comprised 12 organic contaminants (five phosphor organic flame retardants, two musk fragrances, bisphenol A, nonylphenol, octylphenol, diethyltoluamide, terbutryn), 16 polycyclic aromatic hydrocarbons, and 12 heavy metals. Non-metric multidimensional scaling identified organic contaminants that are mainly wastewater-associated (i.e., phosphor organic flame retardants, musk fragrances, and diethyltoluamide) as a major impact variable on macroinvertebrate species composition. The structural degradation of streams was also identified as a significant factor. Multiple linear regression models revealed a significant impact of organic contaminants on invertebrate populations, in particular on Ephemeroptera, Plecoptera, and Trichoptera species. Spearman rank correlation analyses confirmed wastewater-associated organic contaminants as the most significant variable negatively impacting the biodiversity of sensitive macroinvertebrate species. In addition to increased aquatic pollution with organic contaminants, a greater wastewater fraction was accompanied by a slight decrease in oxygen concentration and an increase in salinity. This study highlights the importance of reducing the wastewater-associated impact on surface waters. For aquatic ecosystems in urban areas this would lead to: (i) improvement of the ecological integrity, (ii) reduction of biodiversity loss, and (iii) faster achievement of objectives of legislative requirements, e.g., the European Water Framework Directive