LIMIT CYCLE DYNAMICS ACROSS ELITE MALE ARTISTIC GYMNASTS

Biological systems described by their attractor dynamics provide a method to understand the fundamental characteristics of skilled movement. Here the limit cycle dynamics of the longswing were investigated across tiers of elite men’s gymnasts. Senior, junior and development elite gymnasts (N=21) performed three trials of eight consecutive longswings on high bar. Limit cycle analysis revealed a more symmetrical angular velocity of the centre of mass about the bar trajectory in phase space, higher recurrence, lower correlation dimension and lower variability for senior gymnasts suggesting a more deterministic, efficient and predictive technique. The addition of non-linear dynamics to traditional biomechanics offers complementary theoretical and coaching knowledge to movement coordination, control and skill

DYNAMICS OF A CYCLIC TASK BEFORE AND AFTER A CHANGE IN TASK CONSTRAINT: HORIZONTAL BAR LONGSWING

Returning to a consistent technique after a change in skill allows gymnasts to improve routine fluidity. This study investigates the limit cycle dynamics of the mass centre (CM) after a variation in task constraint during the horizontal bar longswing (LS). Gymnasts (n=12) from 3 different age categories completed 3 x 8 consecutive LS with LS four and five as accelerated LS. Senior gymnasts presented the most consistent limit cycle trajectory and lowest correlation dimension (CD) post- compared to pre- task constraint. Senior gymnasts displayed significantly lower CD post- constraint compared to both junior (p = .016) and development gymnasts (p\u3c .001). The increased proficiency attributed to senior gymnasts appears to increase the stability features of the LS limit cycle of the CM angular velocity after an imposed task constraint which may indicate readiness to progress to more complex horizontal bar skills

Deep Diving into Africa’s Inter-Country Latencies

The Internet in Africa is evolving rapidly, yet remains significantly behind other regions in terms of performance and ubiquity of access. This clearly has negative consequences for the residents of Africa, but also has implications for organisations designing future networked technologies that might see deployment in the region. This paper presents a measurement campaign methodology to explore the current state of the African Internet. Using vantage points across the continent, we perform the first large scale mapping of inter-country delays in Africa. Our analysis reveals a number of clusters, where countries have built up low delay interconnectivity, dispelling the myth that intra-communications in Africa are universally poor. Unfortunately, this does not extend to the remainder of the continent, which typically suffers from excessively high delays, often exceeding 300ms. We find that in many cases it is faster to reach European or North American networks that those in other regions of Africa. By mapping the internetwork topology, we identify a number of shortcomings in the infrastructure, most notably an excessive reliance on intercontinental transit providers

On the potential of Google AMP to promote local content in developing regions

The Google Accelerated Mobile Pages (AMP) project has gained lot of interest from content providers as a means to improve user experience. It introduces a number of innovations to streamline the downloading, parsing and rendering of pages. Google recently announced the hosting of more than 2B+ web pages, covering more than 900K domains. Due to the constrained nature of Internet connectivity in developing regions, AMP offers particularly exciting potential for improving web user experience in these countries. This paper provides a first look at Google’s AMP performance in Africa. We start by outlining the current web infrastructure provisioning in Africa, using local news websites as a case study. Discovering a sparse and low performance environment, we then evaluate the benefits that AMP can introduce in terms of accessibility to local content in developing regions. This study reveals that in Africa, AMP is able to reduce page load time and page size by a factor of 3 and 8 respectively. However, AMP is not a neutral technology as the search engine favours content that is using Google AMP. This raises an important question of search neutrality

Drug-resistant genotypes and multi-clonality in Plasmodium falciparum analysed by direct genome sequencing from peripheral blood of malaria patients.

Naturally acquired blood-stage infections of the malaria parasite Plasmodium falciparum typically harbour multiple haploid clones. The apparent number of clones observed in any single infection depends on the diversity of the polymorphic markers used for the analysis, and the relative abundance of rare clones, which frequently fail to be detected among PCR products derived from numerically dominant clones. However, minority clones are of clinical interest as they may harbour genes conferring drug resistance, leading to enhanced survival after treatment and the possibility of subsequent therapeutic failure. We deployed new generation sequencing to derive genome data for five non-propagated parasite isolates taken directly from 4 different patients treated for clinical malaria in a UK hospital. Analysis of depth of coverage and length of sequence intervals between paired reads identified both previously described and novel gene deletions and amplifications. Full-length sequence data was extracted for 6 loci considered to be under selection by antimalarial drugs, and both known and previously unknown amino acid substitutions were identified. Full mitochondrial genomes were extracted from the sequencing data for each isolate, and these are compared against a panel of polymorphic sites derived from published or unpublished but publicly available data. Finally, genome-wide analysis of clone multiplicity was performed, and the number of infecting parasite clones estimated for each isolate. Each patient harboured at least 3 clones of P. falciparum by this analysis, consistent with results obtained with conventional PCR analysis of polymorphic merozoite antigen loci. We conclude that genome sequencing of peripheral blood P. falciparum taken directly from malaria patients provides high quality data useful for drug resistance studies, genomic structural analyses and population genetics, and also robustly represents clonal multiplicity