214 research outputs found

    The correlation between the health-related fitness of healthy participants measured at home as opposed to fitness measured by sport scientists in a laboratory

    Get PDF
    BACKGROUND : Fitness is defined in the health context as a state of good health or physical condition, primarily as a result of exercise and proper nutrition. Conventional methods of measuring fitness are expensive, time consuming and require specialised methods. There is a need for noninvasive, fast methods of assessing health-related fitness and activity in athlete and non-athlete populations. The aim of this study was to establish any correlation between participants’ self-assessed health-related fitness (HRF) index and the HRF index determined by sports scientists, as well as the laboratory-assessed HRF index and maximum oxygen uptake (VO2max) determined by sports scientists via direct methods in a laboratory, and finally, to determine any potential correlation between an activity-recall questionnaire (Kasari) and VO2max. METHOD : The participants consisted of 169 male and female volunteers between the ages of 18 and 55 years, taking neither supplements nor medication. The University of Pretoria’s HRF index protocol was first carried out by participants on their own at home, and then in the laboratory under the supervision of sport scientists. The complete datasets of 150 participants were statistically analysed to establish correlations. RESULTS : The results indicated highly significant and substantial correlations (ρ = 0.696, p < 0.001) between the participants’ self-assessed HRF index and measurements by the sports scientists. There were moderate correlations between the laboratoryassessed HRF index and the direct VO2max (ρ = 0 512, p < 0.005), as well as the indirect VO2max (ρ = 0.588; p < 0.001). A significant correlation was found between the self-assessed HRF index and the indirect VO2max (ρ = 0.454; p < 0.001). The Kasari questionnaire correlated only weakly with the indirect VO2max (ρ = 0.278, p < 0.002) and not at all with the direct VO2max (ρ = 0.072, p = 0.731). CONCLUSION : Indications are that this test protocol may be conducted at home by individuals, without supervision, to determine exercise ability or fitness, or to monitor changes in physical fitness, thereby limiting expenses and costs.Momentum Interactivehttp://www.safpj.co.za/index.php/safpjhb201

    Representational predicaments for employees: Their impact on perceptions of supervisors\u27 individualized consideration and on employee job satisfaction

    Get PDF
    A representational predicament for a subordinate vis-à-vis his or her immediate superior involves perceptual incongruence with the superior about the subordinate\u27s work or work context, with unfavourable implications for the employee. An instrument to measure the incidence of two types of representational predicament, being neglected and negative slanting, was developed and then validated through an initial survey of 327 employees. A subsequent substantive survey with a fresh sample of 330 employees largely supported a conceptual model linking being neglected and negative slanting to perceptions of low individualized consideration by superiors and to low overall job satisfaction. The respondents in both surveys were all Hong Kong Chinese. Two case examples drawn from qualitative interviews illustrate and support the conceptual model. Based on the research findings, we recommend some practical exercises to use in training interventions with leaders and subordinates. © 2013 Copyright Taylor and Francis Group, LLC

    Fine-Scale Mapping of the 4q24 Locus Identifies Two Independent Loci Associated with Breast Cancer Risk

    Get PDF
    Background: A recent association study identified a common variant (rs9790517) at 4q24 to be associated with breast cancer risk. Independent association signals and potential functional variants in this locus have not been explored. Methods: We conducted a fine-mapping analysis in 55,540 breast cancer cases and 51,168 controls from the Breast Cancer Association Consortium. Results: Conditional analyses identified two independent association signals among women of European ancestry, represented by rs9790517 [conditional P = 2.51 × 10−4; OR, 1.04; 95% confidence interval (CI), 1.02–1.07] and rs77928427 (P = 1.86 × 10−4; OR, 1.04; 95% CI, 1.02–1.07). Functional annotation using data from the Encyclopedia of DNA Elements (ENCODE) project revealed two putative functional variants, rs62331150 and rs73838678 in linkage disequilibrium (LD) with rs9790517 (r2 ≥ 0.90) residing in the active promoter or enhancer, respectively, of the nearest gene, TET2. Both variants are located in DNase I hypersensitivity and transcription factor–binding sites. Using data from both The Cancer Genome Atlas (TCGA) and Molecular Taxonomy of Breast Cancer International Consortium (METABRIC), we showed that rs62331150 was associated with level of expression of TET2 in breast normal and tumor tissue. Conclusion: Our study identified two independent association signals at 4q24 in relation to breast cancer risk and suggested that observed association in this locus may be mediated through the regulation of TET2. Impact: Fine-mapping study with large sample size warranted for identification of independent loci for breast cancer risk

    Physical Processes in Star Formation

    Get PDF
    © 2020 Springer-Verlag. The final publication is available at Springer via https://doi.org/10.1007/s11214-020-00693-8.Star formation is a complex multi-scale phenomenon that is of significant importance for astrophysics in general. Stars and star formation are key pillars in observational astronomy from local star forming regions in the Milky Way up to high-redshift galaxies. From a theoretical perspective, star formation and feedback processes (radiation, winds, and supernovae) play a pivotal role in advancing our understanding of the physical processes at work, both individually and of their interactions. In this review we will give an overview of the main processes that are important for the understanding of star formation. We start with an observationally motivated view on star formation from a global perspective and outline the general paradigm of the life-cycle of molecular clouds, in which star formation is the key process to close the cycle. After that we focus on the thermal and chemical aspects in star forming regions, discuss turbulence and magnetic fields as well as gravitational forces. Finally, we review the most important stellar feedback mechanisms.Peer reviewedFinal Accepted Versio

    JIRAM, the Jovian Infrared Auroral Mapper

    Get PDF
    JIRAM is an imager/spectrometer on board the Juno spacecraft bound for a polar orbit around Jupiter. JIRAM is composed of IR imager and spectrometer channels. Its scientific goals are to explore the Jovian aurorae and the planet's atmospheric structure, dynamics and composition. This paper explains the characteristics and functionalities of the instrument and reports on the results of ground calibrations. It discusses the main subsystems to the extent needed to understand how the instrument is sequenced and used, the purpose of the calibrations necessary to determine instrument performance, the process for generating the commanding sequences, the main elements of the observational strategy, and the format of the scientific data that JIRAM will produce

    The performance of the jet trigger for the ATLAS detector during 2011 data taking

    Get PDF
    The performance of the jet trigger for the ATLAS detector at the LHC during the 2011 data taking period is described. During 2011 the LHC provided proton–proton collisions with a centre-of-mass energy of 7 TeV and heavy ion collisions with a 2.76 TeV per nucleon–nucleon collision energy. The ATLAS trigger is a three level system designed to reduce the rate of events from the 40 MHz nominal maximum bunch crossing rate to the approximate 400 Hz which can be written to offline storage. The ATLAS jet trigger is the primary means for the online selection of events containing jets. Events are accepted by the trigger if they contain one or more jets above some transverse energy threshold. During 2011 data taking the jet trigger was fully efficient for jets with transverse energy above 25 GeV for triggers seeded randomly at Level 1. For triggers which require a jet to be identified at each of the three trigger levels, full efficiency is reached for offline jets with transverse energy above 60 GeV. Jets reconstructed in the final trigger level and corresponding to offline jets with transverse energy greater than 60 GeV, are reconstructed with a resolution in transverse energy with respect to offline jets, of better than 4 % in the central region and better than 2.5 % in the forward direction

    Operation and performance of the ATLAS semiconductor tracker

    Get PDF
    The semiconductor tracker is a silicon microstrip detector forming part of the inner tracking system of the ATLAS experiment at the LHC. The operation and performance of the semiconductor tracker during the first years of LHC running are described. More than 99% of the detector modules were operational during this period, with an average intrinsic hit efficiency of (99.74±0.04)%. The evolution of the noise occupancy is discussed, and measurements of the Lorentz angle, δ-ray production and energy loss presented. The alignment of the detector is found to be stable at the few-micron level over long periods of time. Radiation damage measurements, which include the evolution of detector leakage currents, are found to be consistent with predictions and are used in the verification of radiation background simulations
    corecore