454 research outputs found

    Relationship between saddle and rider kinematics, horse locomotion and thoracolumbar pressures in sound horses

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    Reason for performing the study: Saddle fit is considered to be a crucial factor for the health and performance of horses, yet there is a paucity of scientific data. Objective: To determine the relationship between saddle and rider kinematics, horse locomotion and thoracolumbar pressures in sound horses. Method: Seven horses with asymmetric saddle position were tested before and after correction of the saddle positioning asymmetry. Kinematic and kinetic data were collected using motion capture, inertial sensors and a pressure mapping system. Data of horses showing saddle roll to the right were normalised to represent saddle roll to the left. Results: When comparing saddle roll with saddle correction in trot, this study found that once the saddle had been corrected on the rein with saddle roll to the outside (here: right rein) there was an increase in outside front fetlock hyperextension (P=0.02) and inside hind fetlock hyperextension (P≤0.05); there was a reduction in peak pressures after saddle correction under the inside portion of the panel in trot (P≤0.05) and canter (P=0.04), riders showed increased thoracic side bend (lean) on the contralateral side to the direction of saddle roll (P=0.02). Conclusion: The presence of saddle roll creates changes in fetlock hyperextension and hence likely force production, increased peak pressures beneath the panel on the contralateral side to the direction of saddle roll and affects rider position, with the rider leaning in the opposite direction to saddle roll likely in order to optimise balance

    Longitudinal muon spin relaxation in high purity aluminum and silver

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    The time dependence of muon spin relaxation has been measured in high purity aluminum and silver samples in a longitudinal 2 T magnetic field at room temperature, using time-differential \musr. For times greater than 10 ns, the shape fits well to a single exponential with relaxation rates of \lambda_{\textrm{Al}} = 1.3 \pm 0.2\,(\textrm{stat.}) \pm 0.3\,(\textrm{syst.})\,\pms and \lambda_{\textrm{Ag}} = 1.0 \pm 0.2\,(\textrm{stat.}) \pm 0.2\,(\textrm{syst.})\,\pms

    The pi -> pi pi process in nuclei and the restoration of chiral symmetry

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    The results of an extensive campaign of measurements of the pi -> pi pi process in the nucleon and nuclei at intermediate energies are presented. The measurements were motivated by the study of strong pi pi correlations in nuclei. The analysis relies on the composite ratio C_{pi pi}^A, which accounts for the clear effect of the nuclear medium on the (pi pi) system. The comparison of the C_{pi pi}^A distributions for the (pi pi)_{I=J=0} and (pi pi)_{I=0,J=2} systems to the model predictions indicates that the C_{pi pi}^A behavior in proximity of the 2m_pi threshold is explainable through the partial restoration of chiral symmetry in nuclei.Comment: accepted for publication in Nucl. Phys.

    TRESK is a key regulator of nocturnal suprachiasmatic nucleus dynamics and light adaptive responses

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    The suprachiasmatic nucleus (SCN) is a complex structure dependent upon multiple mechanisms to ensure rhythmic electrical activity that varies between day and night, to determine circadian adaptation and behaviours. SCN neurons are exposed to glutamate from multiple sources including from the retino-hypothalamic tract and from astrocytes. However, the mechanism preventing inappropriate post-synaptic glutamatergic effects is unexplored and unknown. Unexpectedly we discovered that TRESK, a calcium regulated two-pore potassium channel, plays a crucial role in this system. We propose that glutamate activates TRESK through NMDA and AMPA mediated calcium influx and calcineurin activation to then oppose further membrane depolarisation and rising intracellular calcium. Hence, in the absence of TRESK, glutamatergic activity is unregulated leading to membrane depolarisation, increased nocturnal SCN firing, inverted basal calcium levels and impaired sensitivity in light induced phase delays. Our data reveals TRESK plays an essential part in SCN regulatory mechanisms and light induced adaptive behaviours

    A search for two body muon decay signals

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    Lepton family number violation is tested by searching for μ+→e+X0\mu^+\to e^+X^0 decays among the 5.8×108\times 10^8 positive muon decay events analyzed by the TWIST collaboration. Limits are set on the production of both massless and massive X0X^0 bosons. The large angular acceptance of this experiment allows limits to be placed on anisotropic μ+→e+X0\mu^+\to e^+X^0 decays, which can arise from interactions violating both lepton flavor and parity conservation. Branching ratio limits of order 10−510^{-5} are obtained for bosons with masses of 13 - 80 MeV/c2^2 and with different decay asymmetries. For bosons with masses less than 13 MeV/c2^{2} the asymmetry dependence is much stronger and the 90% limit on the branching ratio varies up to 5.8×10−55.8 \times 10^{-5}. This is the first study that explicitly evaluates the limits for anisotropic two body muon decays.Comment: 7 pages, 5 figures, 2 tables, accepted by PR

    General properties of the pion production reaction in nuclear matter

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    The pion production reaction π+→π+π±\pi^+ \to \pi^+\pi^{\pm} on 45Sc^{45}Sc was studied at incident pion energies of Tπ+T_{\pi^{+}} = 240, 260, 280, 300, and 320 MeV. The experiment was performed using the M11M11 pion-channel at TRIUMF, and multiparticle events, (π+,π+π±\pi^+,\pi^+\pi^{\pm}) and (π+,π+π±p\pi^+,\pi^+\pi^{\pm}p), were detected with the CHAOS spectrometer. Results are reported in the form of both differential and total cross sections, and are compared to theoretical predictions and the reaction phase space. The present investigation of the T-dependence of the π+A→π+π±A′\pi^+ A \to \pi^+\pi^{\pm} A' reaction complements earlier examinations of the A-dependence of the reaction, which was measured using 2H^{2}H, 4He^{4}He, 12C^{12}C, 16O^{16}O, 40Ca^{40}Ca, and 208Pb^{208}Pb targets at ∼\sim280 MeV. Some general properties of the pion-induced pion production reaction in nuclear matter will be presented, based on the combined results of the two studies.Comment: 23 pages, Latex, accepted for publication in Nucl. Phys.

    Reflections and Experiences of a Co-Researcher involved in a Renal Research Study

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    Background Patient and Public Involvement (PPI) is seen as a prerequisite for health research. However, current Patient and public involvement literature has noted a paucity of recording of patient and public involvement within research studies. There have been calls for more recordings and reflections, specifically on impact. Renal medicine has also had similar criticisms and any reflections on patient and public involvement has usually been from the viewpoint of the researcher. Roles of patient and public involvement can vary greatly from sitting on an Advisory Group to analysing data. Different PPI roles have been described within studies; one being a co-researcher. However, the role of the co-researcher is largely undefined and appears to vary from study to study. Methods The aims of this paper are to share one first time co-researcher's reflections on the impact of PPI within a mixed methods (non-clinical trial) renal research study. A retrospective, reflective approach was taken using data available to the co-researcher as part of the day-to-day research activity. Electronic correspondence and documents such as meeting notes, minutes, interview thematic analysis and comments on documents were re-examined. The co-researcher led on writing this paper. Results This paper offers a broad definition of the role of the co-researcher. The co-researcher reflects on undertaking and leading on the thematic analysis of interview transcripts, something she had not previously done before. The co-researcher identified a number of key themes; the differences in time and responsibility between being a coresearcher and an Advisory Group member; how the role evolved and involvement activities could match the co-researchers strengths (and the need for flexibility); the need for training and support and lastly, the time commitment. It was also noted that it is preferable that a co-researcher needs to be involved from the very beginning of the grant application. Conclusions The reflections, voices and views of those undertaking PPI has been largely underrepresented in the literature. The role of co-researcher was seen to be rewarding but demanding, requiring a large time commitment. It is hoped that the learning from sharing this experience will encourage others to undertake this role, and encourage researchers to reflect on the needs of those involved.Peer reviewedFinal Published versio
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