Double Bump Research Articles

Is the double bump ankle moment pattern caused by spasticity?

Is the double bump ankle moment pattern caused by spasticity?

A spot check to ensure the quality of matching of kinematic and kinetic data collected during clinical gait analysis

gait this pattern is believed to be due to a dynamic dysbalance of hip flexors and hip extensors. In contrast to a so called ‘single bump’ pattern in hemiplegic gait the identification of a muscles contribution to a ‘double bump’ pattern is difficult because both sides are affected and multi joint muscles are involved. Although the ‘double bump’ is easy to identify by the use of gait analysis the clinical decision making upon the dysbalance depends mostly on static clinical tests. Reduced extension of the hip in terminal stance can be interpreted as a sign of contracture of the M. psoas major. As the hip joint motion in the sagittal plane is easily quantifiable by gait analysis one may take an extension deficit of the hip as a valid parameters for a hip flexor pathology. As trunk position (COG position) sets certain requirements for the range of hip movement it is essential to monitor trunk segment kinematics. Therefore, an extension deficit at the hip joint requires consideration of the trunk position additionally to the influence of multi joint muscles. A forefoot landing presented by a diplegic patient often raises interest in the activation behaviour of the M. triceps surae under dynamic conditions. Spastic muscle behaviour could be identified through qualitative evaluation of high angle accelerations, power absorption-generation patterns or through a sharp increase in high power EMG signals during loading response but by now we know of no valid parameter to quantify muscle activation behaviour in spastic diplegic gait.

Transport‐theoretic model for the electron‐proton‐hydrogen atom aurora: 2. Model results

In the companion paper (Basu et al., this issue), a self‐consistent transport‐theoretic model for the combined electron‐proton‐hydrogen atom aurora was described. In this paper, numerical results based on the model are presented. This is done for the pure electron aurora, the pure proton‐hydrogen atom aurora, and finally for the combined aurora. Adopting commonly used types of energy distributions for the incident particle (electron and proton) fluxes, we give numerical solutions for the precipitating electron, proton, and hydrogen atom differential number fluxes. Results are also given for ionization yields and emission yields of the following features: N2+ first negative group (3914 Å), N2 second positive group (3371 Å), selected N2 Lyman‐Birge‐Hopfield bands (1325 Å, 1354 Å, 1383 Å, 1493 Å, and all bands between 1700 and 1800 Å), O I (1356 Å), Lα (1216 Å), Hβ (4861 Å), and Hα (6563 Å). The yield at 1493 Å also contains a contribution from N I (1493 Å), which in fact dominates LBH emission. A major new result of this study is that the secondary electron flux produced by the proton‐hydrogen atom aurora is much softer than that produced by the electron aurora. This increased softness is due to the fact that (for energies of auroral interest) cross sections for secondary electron production by proton and hydrogen atom impact decrease exponentially with increasing secondary electron energy, whereas the cross sections for electron impact decrease as an inverse power law with increasing secondary energy. In our study of the pure electron aurora (no primary protons or hydrogen atoms present) and the pure proton‐hydrogen atom aurora (no primary electrons present), two important results obtain. First, certain emission features (for example, 3371 Å) are excited in completely different ways for the two kinds of aurora. Second, the "eV per electron‐ion pair" as a function of the characteristic energy E0 is nearly constant for the pure electron aurora, with a value of about 34, but varies by about 20% for the pure proton‐hydrogen atom aurora. In our study of the combined electron‐proton‐hydrogen atom aurora, two additional results obtain. Since the proton‐hydrogen atom contribution to the total incident energy flux in the midnight sector is, on the average, about 20 to 25% of that of the electrons, we find that when it is neglected, the ionization yield as well as the yields of many emission features will be underestimated, on the average, by about the same percentage. We also find that in the morning sector of the combined aurora, a double bump in the altitude profile of the E region electron density is possible for certain auroral conditions.

Inductive response of oriented UPt3 in the superconducting state.

The inductive response of single crystals of ${\mathrm{UPt}}_{3}$ have been studied from 1 K to 70 mK using mutual inductance techniques to measure \ensuremath{\chi}' and \ensuremath{\chi}'' at 31.7 and 317 Hz and tunnel-diode resonant methods at 3 and 16 MHz, for the excitation fields parallel to the symmetry axis of the crystal. A double bump in the \ensuremath{\chi}'' measurements is clearly distinguishable and is consistent with the H=0 phase diagrams of other workers. The temperature dependence of the magnetic penetration depth has been extracted from the measurements, which indicate that the low-frequency results are linear for T/${\mathit{T}}_{\mathit{c}}$0.5, while the high-frequency data indicate a power-law dependence close to ${\mathit{T}}^{2}$.

Charge exchange in heavy ion reactions at relativistic energies

Expressions for cross sections and momentum distributions for charge exchange and charge exchange plus one-nucleon knock-out reactions are derived in Glauber's multiple scattering theory. The production of the Δ(1220) resonance is included and is found to be important. Numerical results for 12C and 16O as projectiles, at 1.05 and 2.10 GeV per nucleon, agree reasonably well with experiment. A double bump structure in the momentum distributions is predicted and subject to experimental verification.