THE INFLUENCE OF STATIC STRETCHING ON THE VISC0ELASTIC PROPERTIES OF M. TRICEPS SURAE

Though the practice of stretching is widely used in sports, general fitness and physiotherapy, there is still a lack of basic research in this area. This study describes the viscoelastic properties of m. triceps surae and investigates the influence of static stretching. 20 males and 11 females, without a history of ankle injury, participated in this experiment. Each testee completed two sessions of seven measurements on an active omnikinetic dynamometer (PROMETT-system). The velocity of the leverarm has been kept constant during all tests (lO°/s). An interactive loop determines the stretching amplitude depending on the force exerted on this lever. The subject was fixated in an adjustable chair, the right leg extended and sustained, the left leg maximally bended in the hip to stabilize the pelvis. Further on, wooden plates were placed between the back of the chair and the pelvis to avoid any hip displacements while exerting force on the foot. After aligning the ankle axis with the axis of the dynamometer, the leverarm was manipulated to determine the moment (Mcrit) and the angle associated with a stretch just short of causing pain. The first and last measurement,of each session was an isokinetic stretch up to Mcrit (Stretch). After a short hold (200 me) in this extreme position (Hold) the same isokinetic movement, but in opposite direction, was used to relax the muscle (Relax). Between-these two 'control measurements' five identic static stretches were performed. These stretches were varied among subgroups regarding the intensity of the Stretch (90% or 100% of Mcrit) and the duration of the Hold (10s or 30 a). Netto joint moments were calculated and expressed relatively as a function of the stretching amplitude. Eighty parameters were selected in order to describe the strain-stretch curves during Stretch and Relax phases and the stress-time curves during the Hold phases. Results obtained by comparing those parameters from first and last control measurements reveal a very stable intra-individual viscoelastic behaviour of the muscle. Though, significant differences in stretching amplitude, creep and parameters describing the shape of the relax curves were observed. Differences between subgroups show a stronger influence of the intensity to the result of the static stretch compared to the influence of a longer Hold phase. In this study females had a significant smaller stretching amplitude then males. They also had less advantages of static stretching

Africa and the Paris Agreement

The African continent is one of the most vulnerable regions to future climate change. Research now demonstrates that constraining anthropogenic warming to 1.5 °C instead of 2 °C will significantly lower the risk of heatwaves to inhabitants.http://www.nature.com/nclimate2018-11-01hj2018Geography, Geoinformatics and Meteorolog

World market or regional integration and food security in West Africa

The problem of food security in West Africa was put on the international agenda in 1974 at the international food conference in Rome following the Great Sahelian Drought of 1968-1973. In those years preoccupation with food security was limited mainly to the Sahel countries and concentrated on estimating the availability and use of resources for grain production. Nowadays, studies in the field of food security focus not only on production, but also on the functioning of the food market, and on consumption and nutrition. This paper concentrates on the debate whether sustainable food security in West Africa will be achieved by protection measures for national food production, by a liberalization of the food trade that facih'tates cheap imports of food from the world market, or by stimulating regional food trade through regional co-operation

Formulary management activities and practice implications among public sector hospital pharmaceutical and therapeutics committees in a South African province

Introduction: The World Health Organization identified Pharmaceutical and Therapeutics Committees (PTCs) at district and hospital levels as one of the pivotal models to promote rational use of medicines (RUM). This is endorsed by the Government in South Africa. Formulary development and management is one of the main functions of PTCs. This study aimed to describe the formulary management activities among PTCs in public hospitals in Gauteng Province, South Africa, following initiatives to promote RUM in South Africa. Methods: Qualitative, nonparticipatory, observational study, observing 26 PTC meetings. Data were coded and categorized using NVivo9 ® qualitative data analysis software. Themes and sub-themes were developed. The themes and sub-themes on formulary management are the principal focus of this paper. Results: More than half of the observed PTCs reviewed their formulary lists. There was variation in the review process among institutions providing different levels of care. Various aspects were considered for formulary management especially requests for medicines to be added. These included cost considerations (mainly focusing on acquisition costs), evidence-based evaluation of clinical trials, patient safety, clinical experience and changes in the National Essential Medicines List (NEML). The tertiary PTCs mostly dealt with applications for new non-EML medicines, while PTCs in the other hospitals mainly requested removal or addition of EML medicines to the list. Conclusion: This is the first study from Gauteng Province, South Africa, reporting on how decisions are actually taken to include or exclude medicines onto formularies within public sector hospitals providing different levels of care. Various approaches are adopted at different levels of care when adding to- or removing medicines from the formulary lists. Future programs should strengthen PTCs in specialized aspects of formulary management. A more structured approach to formulary review at the local PTC level should be encouraged in line with the national approach when reviewing possible additions to the NEML

Comparison of Kinetic Models for Gas Damping of Moving Microbeams

Numerical investigations of the gas flow structure and the gas-damping force on moving and heated microbeams are carried out using the Navier-Stokes equations with first-order velocity-slip and temperature-jump boundary conditions (the NSSJ method) and two kinetic numerical techniques: the particle-based direct simulation Monte Carlo (DSMC) method, and a deterministic discrete-ordinate solution of the ellipsoidal statistical (ES) kinetic model equation. The gas-damping coefficients on a moving microbeam for quasi-static isothermal conditions are estimated by the three numerical methods for Kn = 0.1-1.0. The NSSJ simulations tend to overestimate the gas-damping coefficient for Knudsen numbers larger than 0.1, whereas the DSMC and ES kinetic approaches are in good agreement for the slip and transitional flow regimes. The flow structure and the Knudsen force are calculated using the ES kinetic model for a heated microbeam over a wide range of Knudsen numbers. The Knudsen force peaks in the transitional regime (Kn ≈ 2), and the numerically predicted variation of the force with Knudsen number is consistent with experimentally observed displacements of the heated microbeam