Review of N N Interaction from Lattice QCD

Historically, lattice studies of QCD have concentrated on understanding the properties and structure of an isolated hadron. Recently, there have efforts at understanding the interactions between hadrons. In this talk I will review two approaches to this problem.Comment: 2 pages, 1 postscript figure. To appear in proceedings of Chiral Dynamics 2000, Jefferson Laboratory, July 17-22, 200

Threshold Resonances - a Lattice Perspective

The calculation of the masses of the lightest nucleon resonances using lattice QCD is surveyed. Recent results for the mass of the first radial excitation of the nucleon, the Roper resonance, are reviewed and the interpretation in terms of models of hadronic resonances, such as the quark model and hadronic molecules, discussed. The talk concludes with an outline of prospects for future calculations.Comment: 5 Pages, 2 figures, invited contribution to Focus Session on Nature of Threshold N*, to be published in Proceedings of NSTAR 2002, Pittsburgh, October 9-12, 2002 (World Scientific

Application of inflated structures to hovercraft annual survey 1968-69: inflated structures report C1206/3

1.0 Introduction This report surveys work carried out in the Department of Aircraft Design at the College of Aeronautics, Cranfield, in accordance with the terms of Ministry of Technology contract reference PD/28/045/ADM, College of Aeronautics reference 0.1206. The period covered by this report extends from 1st October 1968 to 1st October 1969, which constitutes the first complete year of operation under the contract terms. The reporting procedure agreed with Mintech is that individual research topics shall be separately reported in the form of technical memoranda, and that comprehensive surveys of a descriptive nature shall be submitted at regular intervals

Bureaucrats, politicians and reform in Whitehall: analysing the bureau-shaping model

Dunleavy's bureau-shaping model has breathed new life into existing debates about the behaviour of senior bureaucrats. This article assesses the utility of this model as an explanation of the development of Next Step agencies in the last decade in Britain, using data drawn from a series of extensive interviews with senior civil servants. Our conclusion is that, although the bureau-shaping model represents a significant advance on previous models of bureaucratic behaviour that stress budget maximization, it is flawed. In particular, we argue that: it pays insufficient attention to the broader political context within which civil servants operate; mis-specifies bureaucrats' preferences; and oversimplifies the distinction between managerial and policy advice work. More specifically, we suggest that any explanation of the development of Next Steps agencies needs to recognize that: politicians rather that civil servants played the major role in their creation; the strategic calculations of bureaucrats were significantly more sophisticated than the model assumes; and the consequence of the reforms has been that senior civil servants have played a greater, rather than a more limited, management role

The measurement of biaxial strains in coated fabric materials using the disc-replica method

A method of measuring biaxial strains in coated fabric type materials is presented whereby the strain is deduced from the distortion of a circular impression made on the material. The impression is placed on the material when loaded, enabling all measurements to be made with the material in its relaxed, unloaded, state

The effect of parallel static and microwave electric fields on excited hydrogen atoms

Motivated by recent experiments we analyse the classical dynamics of a hydrogen atom in parallel static and microwave electric fields. Using an appropriate representation and averaging approximations we show that resonant ionisation is controlled by a separatrix, and provide necessary conditions for a dynamical resonance to affect the ionisation probability. The position of the dynamical resonance is computed using a high-order perturbation series, and estimate its radius of convergence. We show that the position of the dynamical resonance does not coincide precisely with the ionisation maxima, and that the field switch-on time can dramatically affect the ionisation signal which, for long switch times, reflects the shape of an incipient homoclinic. Similarly, the resonance ionisation time can reflect the time-scale of the separatrix motion, which is therefore longer than conventional static field Stark ionisation. We explain why these effects should be observed in the quantum dynamics. PACs: 32.80.Rm, 33.40.+f, 34.10.+x, 05.45.Ac, 05.45.MtComment: 47 pages, 20 figure

Initiating technical refinements in high-level golfers: Evidence for contradictory procedures

When developing motor skills there are several outcomes available to an athlete depending on their skill status and needs. Whereas the skill acquisition and performance literature is abundant, an under-researched outcome relates to the refinement of already acquired and well-established skills. Contrary to current recommendations for athletes to employ an external focus of attention and a representative practice design, Carson and Collins’ (2011) [Refining and regaining skills in fixation/diversification stage performers: The Five-A Model. International Review of Sport and Exercise Psychology, 4, 146–167. doi:10.1080/1750984x.2011.613682] Five-A Model requires an initial narrowed internal focus on the technical aspect needing refinement: the implication being that environments which limit external sources of information would be beneficial to achieving this task. Therefore, the purpose of this paper was to (1) provide a literature-based explanation for why techniques counter to current recommendations may be (temporarily) appropriate within the skill refinement process and (2) provide empirical evidence for such efficacy. Kinematic data and self-perception reports are provided from high level golfers attempting to consciously initiate technical refinements while executing shots onto a driving range and into a close proximity net (i.e. with limited knowledge of results). It was hypothesised that greater control over intended refinements would occur when environmental stimuli were reduced in the most unrepresentative practice condition (i.e. hitting into a net). Results confirmed this, as evidenced by reduced intra-individual movement variability for all participants’ individual refinements, despite little or no difference in mental effort reported. This research offers coaches guidance when working with performers who may find conscious recall difficult during the skill refinement process

“To hit, or not to hit?” Examining the similarity between practice and real swings in golf

Practice swings are commonly employed among golfers, presumably based on the tacit assumption that they share common psychomotor processes with real swings; however, this has not been verified by empirical research. Therefore, this study aimed to examine whether practice swings shared equivalent levels of control to real golf swings, when attempting the same target behavior. Three PGA Professional golf coaches and six amateurs (mean handicap = 2.7, SD = 2.2) each executed 20 swings under two quasirandom conditions; 10 real swings when striking a ball and 10 practice swings without. Underpinned by the theoretical suggestions of the UnControlled Manifold (UCM) approach (Scholz & Schöner, 1999), motor control was assessed using intraindividual movement variability. Results showed the level of equivalence to be inconsistent on both an inter and intraindividual basis. Coaches should, therefore, recognize that practice swings do not share the same effect for every golfer. Optimal coaching needs to consider individual responses before committing to specific training designs if counterproductive training is to be avoided