An Investigation of Exercise-Induced Hypoalgesia After Isometric and Cardiovascular Exercise

Exercise-induced hypoalgesia is a well-established phenomenon in the literature. The underlying mechanisms responsible for this augmentation of pain perception are not completely understood. The specific mode and intensity of exercise that creates hypoalgesia remains equivocal. Therefore, the purpose of this study was to identify if any differences existed in the exercise-induced hypoalgesia of isometric gripping exercise (IGE) and treadmill exercise (TE). A repeated measures design was used to determine the differences in pain threshold between acute exposure to IGE and TE. Twelve healthy male volunteers served as our subjects. Subjects were tested on three different days under three different conditions (rest, IGE, TE). The order of the trials was randomized and applied force (AF) was used as the dependent variable. Applied force pain threshold (AFPT) was determined by a handheld dolorimeter used to apply progressive force and pain to the skin and muscles of the wrist flexors before and after exercise. Exercise induced hypoalgesia was found in both exercise conditions by comparing resting PPT values (6.23 ± 2.04) to those measured immediately after IGE (7.24 ± 1.61; p = 0.0058) or TE (8.03 ± 2.03; p = 0.0001). However, TE produced a larger (22.04 %) hypoanalgesic effect in comparison to isometric exercise (14.14 %). Both TE and IGE may have potential as methods of increasing one’s pressure pain threshold. Further investigation into the specific causes of exercise-induced hypoalgesia is warranted

Approximate supernova remnant dynamics with cosmic ray production

Supernova explosions are the most violent and energetic events in the galaxy and have long been considered probably sources of Cosmic Rays. Recent shock acceleration models treating the Cosmic Rays (CR's) as test particles nb a prescribed Supernova Remnant (SNR) evolution, indeed indicate an approximate power law momentum distribution f sub source (p) approximation p(-a) for the particles ultimately injected into the Interstellar Medium (ISM). This spectrum extends almost to the momentum p = 1 million GeV/c, where the break in the observed spectrum occurs. The calculated power law index approximately less than 4.2 agrees with that inferred for the galactic CR sources. The absolute CR intensity can however not be well determined in such a test particle approximation

Onion-shell model for cosmic ray electrons and radio synchrotron emission in supernova remnants

The spectrum of cosmic ray electrons, accelerated in the shock front of a supernova remnant (SNR), is calculated in the test-particle approximation using an onion-shell model. Particle diffusion within the evolving remnant is explicity taken into account. The particle spectrum becomes steeper with increasing radius as well as SNR age. Simple models of the magnetic field distribution allow a prediction of the intensity and spectrum of radio synchrotron emission and their radial variation. The agreement with existing observations is satisfactory in several SNR's but fails in other cases. Radiative cooling may be an important effect, especially in SNR's exploding in a dense interstellar medium

In which shell-type SNRs should we look for gamma-rays and neutrinos from p-p collisions?

We present a simple analytic model for the various contributions to the non-thermal emission from shell type SNRs, and show that this model's results reproduce well the results of previous detailed calculations. We show that the \geq 1 TeV gamma ray emission from the shell type SNRs RX J1713.7-3946 and RX J0852.0-4622 is dominated by inverse-Compton scattering of CMB photons (and possibly infra-red ambient photons) by accelerated electrons. Pion decay (due to proton-proton collisions) is shown to account for only a small fraction, \lesssim10^-2, of the observed flux, as assuming a larger fractional contribution would imply nonthermal radio and X-ray synchrotron emission and thermal X-ray Bremsstrahlung emission that far exceed the observed radio and X-ray fluxes. Models where pion decay dominates the \geq 1 TeV flux avoid the implied excessive synchrotron emission (but not the implied excessive thermal X-ray Bremsstrahlung emission) by assuming an extremely low efficiency of electron acceleration, K_ep \lesssim 10^-4 (K_ep is the ratio of the number of accelerated electrons and the number of accelerated protons at a given energy). We argue that observations of SNRs in nearby galaxies imply a lower limit of K_ep \gtrsim 10^-3, and thus rule out K_ep values \lesssim 10^-4 (assuming that SNRs share a common typical value of K_ep). It is suggested that SNRs with strong thermal X-ray emission, rather than strong non-thermal X-ray emission, are more suitable candidates for searches of gamma rays and neutrinos resulting from proton-proton collisions. In particular, it is shown that the neutrino flux from the SNRs above is probably too low to be detected by current and planned neutrino observatories (Abridged).Comment: 13 pages, 1 figure, accepted for publication in JCAP, minor revision

Getting to know Pepper : Effects of people’s awareness of a robot’s capabilities on their trust in the robot

© 2018 Association for Computing MachineryThis work investigates how human awareness about a social robot’s capabilities is related to trusting this robot to handle different tasks. We present a user study that relates knowledge on different quality levels to participant’s ratings of trust. Secondary school pupils were asked to rate their trust in the robot after three types of exposures: a video demonstration, a live interaction, and a programming task. The study revealed that the pupils’ trust is positively affected across different domains after each session, indicating that human users trust a robot more the more awareness about the robot they have