[Purpose] The effect of duration of smartphone use on neck and shoulder muscle fatigue and pain was investigated in adults with forward head posture. [Subjects and Methods] Thirty-four adults with forward head posture were classified into groups by duration of smartphone use: 11 used a smartphone for 10 minutes each (group 1), 12 for 20 minutes each (group 2), and 11 for 30 minutes each (group 3). Fatigue cervical erector spinae and upper trapezius muscles was measured by electromyography, and pain before and after the experiment was evaluated using Visual Analog Scale (VAS) scores. [Results] There was a significant difference in the degree of fatigue in the left upper trapezius muscles in group 2 and left cervical erector spinae and bilateral upper trapeziuses group 3. There was a significant difference in fatigue in the left upper trapezius in groups 1 and 3. The VAS showed significant differences in all groups before and after the experiment and between groups 1 and 3. [Conclusion] Pain and fatigue worsened with longer smartphone use. This study provided data on the proper duration of smartphone use. Correct posture and breaks of at least 20 minutes are recommend when using smartphones.

[1] We investigated the impact of subseasonal basic-state changes on Rossby wave propagation between July and August. Our investigation was based on an experimental study that used a linear baroclinic model. Two sets of diabatic heating were imposed at the midlatitudes and the tropics. It was found that, by a principal component analysis, the atmospheric response to diabatic heating reaches a steady state on day 15. Thus, the response to midlatitude forcing reveals eastward Rossby wave propagation along the Asian jet, while that to tropical forcing shows a Gill-type response followed by propagation into the extratropics. The basic state differences between July and August are mainly revealed by thermal and dynamical effects: a strong land-sea thermal contrast and meridional shift of the Asian jet. With regard to midlatitude forcing, the Rossby wave response under the August basic state is higher than that under the July basic state. This can be attributed primarily to the dynamical effect of the basic state. On the other hand, the Rossby wave response to tropical forcing shows stronger amplitude under the July basic state than the August basic state. The response is caused mainly by both the thermal and dynamical effects of the basic state. In addition, the interdecadal change in the basic state induces a significant change in the Rossby wave propagation. The difference is most evident in the change to midlatitude forcing that is due to the dynamical effect of the basic state.

Plasma wakefield acceleration is a promising technology to reduce the size of particle accelerators. The use of high energy protons to drive wakefields in plasma has been demonstrated during Run 1 of the AWAKE programme at CERN. Protons of energy 400 GeV drove wakefields that accelerated electrons to 2 GeV in under 10 m of plasma. The AWAKE collaboration is now embarking on Run 2 with the main aims to demonstrate stable accelerating gradients of 0.5–1 GV/m, preserve emittance of the electron bunches during acceleration and develop plasma sources scalable to 100s of metres and beyond. By the end of Run 2, the AWAKE scheme should be able to provide electron beams for particle physics experiments and several possible experiments have already been evaluated. This article summarises the programme of AWAKE Run 2 and how it will be achieved as well as the possible application of the AWAKE scheme to novel particle physics experiments.

No abstract