Blue-tilted Primordial Gravitational Waves from Massive Gravity

We study a theory of massive tensor gravitons which predicts blue-tilted and largely amplified primordial gravitational waves. After inflation, while their mass is significant until it diminishes to a small value, gravitons are diluted as non-relativistic matter and hence their amplitude can be substantially amplified compared to the massless gravitons which decay as radiation. We show that such gravitational waves can be detected by interferometer experiments, even if their signal is not observed on the CMB scales.Comment: 6 pages, 2 figure

BIOMECHANICAL STUDY ON DIFFERENT DIRECTIONS FOR RUNNING JUMPS FOCUSED ON THE TAKEOFF PREPARATION

This study aimed to elucidate the difference in CG parameters from three steps, prejump to takeoff step of the jump motion (running jump), and obtain primary data on takeoff preparation action. Five male jumpers associated with the university track and field department were trained to perform their best at (1) approach run with no takeoff (RUN), (2) jumping as far as possible (long jump [LJ]), and (3) jumping as high as possible (high jump [HJ]), which were recorded using a three-dimensional capture system. As a result, significant differences were observed in not only the takeoff but also the takeoff preparation phase regarding CG parameters, suggesting the need to focus on the takeoff preparation phase as a factor that determines jump direction. Moreover, HJ and LJ suppressed an increase in vertical velocity one step prior, and by takeoff at a lower CG, the athletes allowed for an easier increase in takeoff angle and jump height. However, to resist a decrease in horizontal velocity, LJ transitioned to takeoff in a manner closer to RUN and without changing takeoff preparation as much as that in HJ. Thus, adjusting vertical velocity and height one step before takeoff can influence takeoff angle