391 research outputs found

    Tracking 6 Weeks of training/surfing sessions of adolescent competitive surfers: Just what are these young surfers up to?

    Get PDF
    The assessment of weekly and even monthly surf practice/training hours is vital for understanding the loads these up and coming surfers endure. Such information will help understand what kind of training these athletes are undertaking, how long they are surfing, what they consider training, and also areas that should be improved upon in terms of specific training. The purpose of this study was to establish surfers\u27 training hours in terms of strength, balance and conditioning hours, as well as surfing hours, coached hours and competition hours. The monitoring of the athletes will provide insights into the weekly surf hours compared to land-based training these athletes do.https://ro.ecu.edu.au/ecuposters/1008/thumbnail.jp

    Counting Complex Disordered States by Efficient Pattern Matching: Chromatic Polynomials and Potts Partition Functions

    Full text link
    Counting problems, determining the number of possible states of a large system under certain constraints, play an important role in many areas of science. They naturally arise for complex disordered systems in physics and chemistry, in mathematical graph theory, and in computer science. Counting problems, however, are among the hardest problems to access computationally. Here, we suggest a novel method to access a benchmark counting problem, finding chromatic polynomials of graphs. We develop a vertex-oriented symbolic pattern matching algorithm that exploits the equivalence between the chromatic polynomial and the zero-temperature partition function of the Potts antiferromagnet on the same graph. Implementing this bottom-up algorithm using appropriate computer algebra, the new method outperforms standard top-down methods by several orders of magnitude, already for moderately sized graphs. As a first application, we compute chromatic polynomials of samples of the simple cubic lattice, for the first time computationally accessing three-dimensional lattices of physical relevance. The method offers straightforward generalizations to several other counting problems.Comment: 7 pages, 4 figure

    Exact T=0 Partition Functions for Potts Antiferromagnets on Sections of the Simple Cubic Lattice

    Full text link
    We present exact solutions for the zero-temperature partition function of the qq-state Potts antiferromagnet (equivalently, the chromatic polynomial PP) on tube sections of the simple cubic lattice of fixed transverse size Lx×LyL_x \times L_y and arbitrarily great length LzL_z, for sizes Lx×Ly=2×3L_x \times L_y = 2 \times 3 and 2×42 \times 4 and boundary conditions (a) (FBCx,FBCy,FBCz)(FBC_x,FBC_y,FBC_z) and (b) (PBCx,FBCy,FBCz)(PBC_x,FBC_y,FBC_z), where FBCFBC (PBCPBC) denote free (periodic) boundary conditions. In the limit of infinite-length, LzL_z \to \infty, we calculate the resultant ground state degeneracy per site WW (= exponent of the ground-state entropy). Generalizing qq from Z+{\mathbb Z}_+ to C{\mathbb C}, we determine the analytic structure of WW and the related singular locus B{\cal B} which is the continuous accumulation set of zeros of the chromatic polynomial. For the LzL_z \to \infty limit of a given family of lattice sections, WW is analytic for real qq down to a value qcq_c. We determine the values of qcq_c for the lattice sections considered and address the question of the value of qcq_c for a dd-dimensional Cartesian lattice. Analogous results are presented for a tube of arbitrarily great length whose transverse cross section is formed from the complete bipartite graph Km,mK_{m,m}.Comment: 28 pages, latex, six postscript figures, two Mathematica file

    Assessment of the 2016 National Institute for Health and Care Excellence high-sensitivity troponin rule-out strategy.

    Get PDF
    OBJECTIVE: We aimed to evaluate the limit of detection of high-sensitivity troponin (hs-cTn) and Thrombolysis In Myocardial Infarction (TIMI) score combination rule-out strategy suggested within the 2016 National Institute for Health and Care Excellence (NICE) Chest Pain of Recent Onset guidelines and establish the optimal TIMI score threshold for clinical use. METHODS: A pooled analysis of adult patients presenting to the emergency department with chest pain and a non-ischaemic ECG, recruited into six prospective studies, from Australia, New Zealand and the UK. We evaluated the sensitivity of TIMI score thresholds from 0 to 2 alongside hs-cTnT or hs-cTnI for the primary outcome of major adverse cardiac events within 30 days. RESULTS: Data were available for 3159 patients for hs-cTnT and 4532 for hs-cTnI, of these 376 (11.9%) and 445 (9.8%) had major adverse cardiac events, respectively. Using a TIMI score of 0, the sensitivity for the primary outcome was 99.5% (95% CI 98.1% to 99.9%) alongside hs-cTnT and 98.9% (97.4% to 99.6%)%) alongside hs-cTnI, identifying 17.9% and 21.0% of patients as low risk, respectively. For a TIMI score ≤1 sensitivity was 98.9% (97.3% to 99.7%)%) alongside hs-cTnT and 98.4% (96.8% to 99.4%)%) alongside hs-cTnI, identifying 28.1% and 35.7% as low risk, respectively. For TIMI≤2, meta-sensitivity was <98% with either assay. CONCLUSIONS: Our findings support the rule-out strategy suggested by NICE. The TIMI score threshold suggested for clinical use is 0. The proportion of patients identified as low risk (18%-21%) and suitable for early discharge using this threshold may be sufficient to encourage change of practice. TRIAL REGISTRATION NUMBERS: ADAPT observational study/IMPACT intervention trial ACTRN12611001069943.ADAPT-ADP randomised controlled trial ACTRN12610000766011.EDACS-ADP randomised controlled trial ACTRN12613000745741.TRUST observational study ISRCTN no. 21109279

    Lower Bounds and Series for the Ground State Entropy of the Potts Antiferromagnet on Archimedean Lattices and their Duals

    Full text link
    We prove a general rigorous lower bound for W(Λ,q)=exp(S0(Λ,q)/kB)W(\Lambda,q)=\exp(S_0(\Lambda,q)/k_B), the exponent of the ground state entropy of the qq-state Potts antiferromagnet, on an arbitrary Archimedean lattice Λ\Lambda. We calculate large-qq series expansions for the exact Wr(Λ,q)=q1W(Λ,q)W_r(\Lambda,q)=q^{-1}W(\Lambda,q) and compare these with our lower bounds on this function on the various Archimedean lattices. It is shown that the lower bounds coincide with a number of terms in the large-qq expansions and hence serve not just as bounds but also as very good approximations to the respective exact functions Wr(Λ,q)W_r(\Lambda,q) for large qq on the various lattices Λ\Lambda. Plots of Wr(Λ,q)W_r(\Lambda,q) are given, and the general dependence on lattice coordination number is noted. Lower bounds and series are also presented for the duals of Archimedean lattices. As part of the study, the chromatic number is determined for all Archimedean lattices and their duals. Finally, we report calculations of chromatic zeros for several lattices; these provide further support for our earlier conjecture that a sufficient condition for Wr(Λ,q)W_r(\Lambda,q) to be analytic at 1/q=01/q=0 is that Λ\Lambda is a regular lattice.Comment: 39 pages, Revtex, 9 encapsulated postscript figures, to appear in Phys. Rev.

    Theory of Distinct Crystal Structures of Polymerized Fullerides AC60, A=K, Rb, Cs: the Specific Role of Alkalis

    Full text link
    The polymer phases of AC60 form distinct crystal structures characterized by the mutual orientations of the (C60-)n chains. We show that the direct electric quadrupole interaction between chains always favors the orthorhombic structure Pmnn with alternating chain orientations. However the specific quadrupolar polarizability of the alkali metal ions leads to an indirect interchain coupling which favors the monoclinic structure I2/m with equal chain orientations. The competition between direct and indirect interactions explains the structural difference between KC60 and RbC60, CsC60.Comment: 4 pages, 2 figures, 1 tabl

    Relaxation dynamics and ionic conductivity in a fragile plastic crystal

    Full text link
    We report a thorough characterization of the dielectric relaxation behavior and the ionic conductivity in the plastic-crystalline mixture of 60% succinonitrile and 40% glutaronitrile. The plastic phase can be easily supercooled and the relaxational behavior is investigated by broadband dielectric spectroscopy in the liquid, plastic crystalline, and glassy crystal phases. The very pronounced alpha-relaxation found in the spectra is characterized in detail. From the temperature dependence of the alpha-relaxation time, a fragility parameter of 62 was determined making this material one of the most fragile plastic-crystalline glass formers. A well-pronounced secondary and faint indications for a third relaxation process were found, the latter most likely being of Johari-Goldstein type. In addition, relatively strong conductivity contributions were detected in the spectra exhibiting the typical features of ionic charge transport.Comment: 8 pages, 7 figure

    Training opportunities in thoracic ultrasound for respiratory trainees: are current guidelines practical?

    Get PDF
    Respiratory trainees in the UK face challenges in meeting current Royal College of Radiologists (RCR) Level 1 training requirements for thoracic ultrasound (TUS) competence, specified as attending 'at least one session per week over a period of no less than 3 months, with approximately five scans per session performed by the trainee (under supervision of an experienced practitioner)'. We aimed to clarify where TUS training opportunities currently exist for respiratory registrars.This is an Open Access article. Click on the Publisher URL to access the full-text

    Identification of a cytokine network sustaining neutrophil and Th17 activation in untreated early rheumatoid arthritis

    Get PDF
    © 2010 Cascão et al.; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Introduction: Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease characterized by sustained synovitis. Recently, several studies have proposed neutrophils and Th17 cells as key players in the onset and perpetuation of this disease. The main goal of this work was to determine whether cytokines driving neutrophil and Th17 activation are dysregulated in very early rheumatoid arthritis patients with less than 6 weeks of disease duration and before treatment (VERA). Methods: Cytokines related to neutrophil and Th17 activation were quantified in the serum of VERA and established RA patients and compared with other very early arthritis (VEA) and healthy controls. Synovial fluid (SF) from RA and osteoarthritis (OA) patients was also analyzed. Results: VERA patients had increased serum levels of cytokines promoting Th17 polarization (IL-1b and IL-6), as well as IL-8 and Th17-derived cytokines (IL-17A and IL-22) known to induce neutrophil-mediated inflammation. In established RA this pattern is more evident within the SF. Early treatment with methotrexate or corticosteroids led to clinical improvement but without an impact on the cytokine pattern. Conclusions: VERA patients already display increased levels of cytokines related with Th17 polarization and neutrophil recruitment and activation, a dysregulation also found in SF of established RA. 0 Thus, our data suggest that a cytokine-milieu favoring Th17 and neutrophil activity is an early event in RA pathogenesis.This work was supported by a grant from Sociedade Portuguesa de Reumatologia/Schering-Plough 2005. RAM and RC were funded by Fundação para a Ciência e a Tecnologia (FCT) SFRH/BD/30247/2006 and SFRH/BD/40513/2007, respectively. MMS-C was funded by Marie Curie Intra-European Fellowship PERG-2008-239422 and a EULAR Young Investigator Award

    Scoring analysis of the men’s 2014, 2015 and 2016 world championship tour of surfing: the importance of aerial manoeuvres in competitive surfing.

    Get PDF
    The aim of this study was to investigate the impact of aerial manoeuvres on scoring in professional surfing. 23631 waves were analysed for the number and types of aerial manoeuvres performed from the 2014, 2015 and 2016 Men's World Championship Tour. Additionally, the awarded score, timing and order of the aerial was also analysed. Descriptive statistics and Two Way ANOVA's were performed with Sidak Multiple Comparisons Post Hoc analysis. Results were a significantly higher score being awarded (P?0.0001) when including an aerial in competition across all three seasons. In 2015 surfers were awarded a significantly larger score when performing an air reverse, compared to 2014 (P=0.0002) and 2016 (P=0.0057). Surfers were also awarded a higher score for the full rotation aerial in 2015 compared to 2014 (P=0.0177). In 2015 surfers performing forehand aerials were awarded a greater score than in 2016 (P=0.0113). The timing of the aerial and score awarded was significantly greater in 2015 as opposed to 2014 when the aerial was their final manoeuvre (P&lt; 0.0001) and when surfers timed the aerial performance early within the heat (P = 0.0027). If a surfer incorporates an aerial manoeuvre during competition, generally speaking, they will be awarded a significantly higher score
    corecore