Peak Compression Force Physics in Rugby Union Scrum

Scrums play a major role in Rugby Union games, and are historically known as a showdown between the two packs of opposing teams, composed of their eight forwards players organized in a 3-4-1 configuration, respectively. We investigate scrum mechanics by working with professional male forward players from Racing 92, a high-level French Rugby club, and measuring the forces they apply on the French Rugby Federation instrumented scrum machine. Signal analysis reveals two major phases in the force production during a scrummaging effort: an impulsive engagement force, and then a force sustained for a few seconds. We experimentally compare individual performances of the engagement phase. We discuss the influence of the mass and the engagement speed of the players, and we introduce the model we are investigating to describe the individual impact on a scrum machine. We expect this model to be the elementary component of a collective model of a pack.

Cognitive Arithmetic: Evidence for Right Hemispheric Mediation in an Elementary Component Stage

Earlier studies involving the lateralization of arithmetic abilities have provided evidence for both right and left hemisphere superiorities. It is argued here that part of this inconsistency could be due to the complexity of the arithmetic computations which have been examined. The present studies examined a subprocess shown to be involved in more complex tasks, such as subtraction. The subprocess is the identification of which of two numbers is greater, and was tested by the flashing of a pair of digits to either the left or right visual field. Errors, reaction-times to make a decision, and examination of hand × visual field interactions all indicated that this subprocess is mediated by the right hemisphere. Correlational analysis was used to identify the operations underlying the observed lateralization of this ability. This analysis indicated that an operation indexed by the spatial order in which the digits were presented was effective in the right hemisphere but not the left hemisphere. Speculations on the nature of these operations were presented.

TRANSFORMATION OF IRREGULAR WAVES IN SHOALING WATER

In the numerical method of prediction of wind waves in deep water, Hasselmann's nonlinear interaction theory is applied. This method assumes the energy balance of individual component waves. However, the total energy balance must exist in the transformation of irregular waves in shoaling water. In this investigation, experiments were carried out on the transformations in shoaling water of composite waves having two components and random waves having one or two main peaks. It was found that the elementary component wave height of the composite waves and the elementary peak power of the random waves decrease with decrease in the water depth. This reason can be explained qualitatively by the theory of the elementary component wave height change of finite amplitude waves in shoaling water. The secondary component wave height of the composite waves and the secondary peak power of the random waves increase with decrease in the water depth. This can be explained qualitatively by Hamada's theory of nonlinear interaction in uniform depth.