Fast Entropy Estimation for Natural Sequences

It is well known that to estimate the Shannon entropy for symbolic sequences accurately requires a large number of samples. When some aspects of the data are known it is plausible to attempt to use this to more efficiently compute entropy. A number of methods having various assumptions have been proposed which can be used to calculate entropy for small sample sizes. In this paper, we examine this problem and propose a method for estimating the Shannon entropy for a set of ranked symbolic natural events. Using a modified Zipf-Mandelbrot-Li law and a new rank-based coincidence counting method, we propose an efficient algorithm which enables the entropy to be estimated with surprising accuracy using only a small number of samples. The algorithm is tested on some natural sequences and shown to yield accurate results with very small amounts of data

Strongman training – Needs analysis and integration into strength and conditioning programming: part 2.

The article aims to evaluate the integration of strongman based exercises within the practice of strength and conditioning. It should give the reader a clear understanding of the specific physiological and biomechanical traits of each of the exercises discussed in the previous article. This information will then be used to discuss its amalgamation within traditional based exercises within the planning of a periodised programme for strength and conditioning practitioners

Doping of inorganic materials in microreactors – preparation of Zn doped Fe₃O₄ nanoparticles

Microreactor systems are now used more and more for the continuous production of metal nanoparticles and metal oxide nanoparticles owing to the controllability of the particle size, an important property in many applications. Here, for the first time, we used microreactors to prepare metal oxide nanoparticles with controlled and varying metal stoichiometry. We prepared and characterised Zn-substituted Fe₃O₄ nanoparticles with linear increase of Zn content (ZnxFe₃−xO₄ with 0 ≤ x ≤ 0.48), which causes linear increases in properties such as the saturation magnetization, relative to pure Fe₃O₄. The methodology is simple and low cost and has great potential to be adapted to the targeted doping of a vast array of other inorganic materials, allowing greater control on the chemical stoichiometry for nanoparticles prepared in microreactors

Validity and reliability of the ‘Isometric Exercise Scale’ (IES) for measuring ratings of perceived exertion during continuous isometric exercise

Purpose: Isometric exercise (IE) interventions have been shown to be effective at reducing resting arterial blood pressure (BP). IE intensity is generally determined using force, electromyography (EMG), heart rate (HR), or knee joint angle. However, ratings of perceived exertion (RPE) may provide a more accessible means of determining exercise intensity. Therefore, the aim of this study was to assess the validity of a specific Isometric Exercise Scale (IES) during a continuous incremental isometric wall squat test. Methods: Twenty-nine male participants completed 4 incremental IE tests. Each test consisted of 5 isometric wall squat intensities, determined by knee joint angles from 135° to 95°, each held for up to 2 minutes. The tests were continuous until volitional fatigue or completion of the 5 work stages. Throughout the exercise protocol, RPE (IES and Borg’s CR-10), HR and blood pressure were recorded. Results: The IES produced a strong positive linear relationship with the CR-10 (r = 0.967) . Additionally, strong positive relationships between the IES and wall squat duration (r = 0.849), HR (r = 0.819) and BP (r = 0.841) were seen. Intra-class correlation coefficients and coefficients of variations for the IES ranged from r = 0.81 to 0.91 and 4.5% to 54% respectively, with greater reliability seen at the higher workloads. Conclusions: The IES is a valid and reliable measure of RPE, exercise intensity, and it accurately represents the changes in physiological measures of exertion during IE; as such, the IES can be used as a useful additional measure of exercise intensity during IET interventions

Strongman training – a rationale for its inclusion in strength & conditioning: part 1

This article, the first in a two-part series, aims to introduce the concepts of strongman-type training relative to some of the exercises adopted. It should give the reader a detailed background into the evolution of strongman training with a strong rationale for its inclusion within the practice of strength and conditioning

Partial swing golf shots: scaled from full swing or independent technique?

During practice and competition, golfers are required to use submaximal effort to hit the ball a given distance, i.e. perform a partial shot. While the full golf swing has undergone extensive research, little has addressed partial shots and the biomechanical modifications golfers employ. This study investigates the biomechanical changes between full and partial swings, and determines if the partial swing is a scaled version of the full swing. Using a repeated measures design, thirteen male golfers completed a minimum of 10 swings in the full and partial swing conditions, whilst club, ball, kinematic and kinetic parameters were recorded. Large and statistically significant reductions in body motion (centre of pressure ellipse: 33%, p = 0.004 , d = 2.26), combined with moderate reductions in lateral shift (25.5%, p = 0.004, d = 0.332) and smaller reductions in trunk rotation (arm to vertical at top of backswing: 14.1%, p = 0.002, d = 2.58) indicate golfers favour larger reductions in proximal measures, combined with diminished reductions as variables moved distally. Furthermore, the partial swing was not found to be a scaled version of the full swing implying a new approach to coaching practices might be considered

Copper(I) Chloride Carbonyl Polymers

Addition of bridging diamine ligands to methanolic solutions of CuCl under a CO purge produces the polymeric complexes [(CuCl)2(CO)2(biL)] (biL = diazabicyclo[2.2.2]octane (DABCO), piperazine (Pip), N,N‘-dimethylpiperazine (DMP)). X-ray crystal structures of the three complexes reveal rhombic OC−Cu(μ-Cl)2Cu−CO bridged by biL. Unsaturated bridging ligands fail to produce carbonyl-bearing products

Validity and reliability of RPE as a measure of intensity during isometric wall squat exercise

Background and Aims: Isometric exercise (IE), including wall squat training, has been shown to be effective at reducing resting blood pressure (BP). Rating of perceived exertion (RPE) is also widely used as an accessible additional measure of IE intensity. Despite this, no RPE scales have been specifically designed for use with IE and it is not clear whether RPE is sensitive enough to distinguish between different lower limb IE workloads. Therefore, the aims of this study were to assess the validity and reliability of RPE as a measure of IE intensity (workload) and physiological exertion (Heart rate and BP), and to examine whether RPE is able to discern differences in wall squat workload (knee angle) at a resolution of 10-degrees, as was previous shown for heart rate (HR) and BP. Methods: Twenty-nine male participants completed 8 separate isometric wall squat testing sessions, separated by a minimum of 5-hours. Each session consisted of a single 2-minute isometric wall squat test, at one of five randomised workloads (knee joint angles). Three of the knee angles were repeated, a second time, to allow measurements of reliability. Throughout the exercise protocol, HR and BP were recorded continuously; values for each 30-second time-point were calculated as the mean of the proceeding 5-seconds, peak values for the 2-minute bout were taken as the mean results for the final 5- seconds of the bout. Additionally, mean results for the full 2-minute period were calculated. RPE was collected every 30 seconds. Concurrent validity was assessed by correlating RPE results with the criterion measures: Knee joint angle, HR and BP. Differences in RPE were assessed across consecutive workloads and time-points. Results: There were significant increases in RPE at each consecutive wall squat workload (p < 0.001) and between each consecutive 30-second time point (p < 0.001). Additionally, the RPE results produced a significant inverse relationship with knee angle (r = -0.79; p < 0.001) and significant positive relationships with HR (r = 0.53, p < 0.001) and BP (systolic: r = 0.77; diastolic: r = 0.62; mean arterial pressure: r = 0.70, p < 0.001). Conclusion: RPE provides a valid and reliable measure of isometric wall squat intensity, physiological exertion, and can discern between knee angles with a resolution of 10°. Relevance for patients: Patients and practitioners implementing isometric exercise training for arterial blood pressure reduction can use RPE to accurately monitor the intensity of the exercise and the physiological responses