Vector-field statistics for the analysis of time varying clinical gait data.

BACKGROUND: In clinical settings, the time varying analysis of gait data relies heavily on the experience of the individual(s) assessing these biological signals. Though three dimensional kinematics are recognised as time varying waveforms (1D), exploratory statistical analysis of these data are commonly carried out with multiple discrete or 0D dependent variables. In the absence of an a priori 0D hypothesis, clinicians are at risk of making type I and II errors in their analyis of time varying gait signatures in the event statistics are used in concert with prefered subjective clinical assesment methods. The aim of this communication was to determine if vector field waveform statistics were capable of providing quantitative corroboration to practically significant differences in time varying gait signatures as determined by two clinically trained gait experts. METHODS: The case study was a left hemiplegic Cerebral Palsy (GMFCS I) gait patient following a botulinum toxin (BoNT-A) injection to their left gastrocnemius muscle. FINDINGS: When comparing subjective clinical gait assessments between two testers, they were in agreement with each other for 61% of the joint degrees of freedom and phases of motion analysed. For tester 1 and tester 2, they were in agreement with the vector-field analysis for 78% and 53% of the kinematic variables analysed. When the subjective analyses of tester 1 and tester 2 were pooled together and then compared to the vector-field analysis, they were in agreement for 83% of the time varying kinematic variables analysed. INTERPRETATION: These outcomes demonstrate that in principle, vector-field statistics corroborates with what a team of clinical gait experts would classify as practically meaningful pre- versus post time varying kinematic differences. The potential for vector-field statistics to be used as a useful clinical tool for the objective analysis of time varying clinical gait data is established. Future research is recommended to assess the usefulness of vector-field analyses during the clinical decision making process

A surface science approach to understand CO and NO chemistry on Au surfaces

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INELASTIC NEUTRON SCATTERING ON THE SPIN GLASS : PdMn 10 - at. %

Par la contribution inélastique de la diffusion de neutrons à un verre de spin Pd-Mn on a déterminé la répartition de probabilités d'énergies de couplage P(E) qui paraît être en bon accord avec les résultats d'une simulation numérique. La chaleur spécifique, calculée selon cette répartition, est conforme aux résultats expérimentaux.From the inelastic contribution to the neutron scattering on a Pd-Mn spin glass the probability distribution P(E) of exchange energies was determined which was in good agreement with computer simulation results. From this P(E), the specific heat could be calculated with close conformity to experiment

Methanol decomposition and oxidation on Ir(111)

The adsorption, decompn., and oxidn. of methanol (CH3OH) has been studied on Ir(111) using temp.-programmed desorption and high-energy resoln. fast XPS. Mol. methanol desorption from a methanol-satd. surface at low temp. shows three desorption peaks, around 150 K (alpha ), around 170 K (beta 1), and around 220 K (beta 2), resp. The alpha peak is assigned to methanol adsorbed on top of the first, chemisorbed layer, whereas beta 1 and beta 2 are both assigned to methanol directly coordinated to the metal surface atoms (chemisorbed). The CH3OHad responsible for the beta 2 desorption peak appears as a sep. component in the C 1s core level spectra. A part of the initially adsorbed methanol decomps. into COad and Had around (or even below) 175 K. Intermediate CHxO species of CH3OH decompn. were not obsd. The formation of a small amt. of CHxad indicates that (Hx)C-O(H) bond scission occurs as well. Temp.-programmed desorption expts. confirm that CHxad species form, as evidenced by a high-temp. (500 K) H2 formation peak due to decompn. of CHad. The presence of Oad causes a downward shift in the C 1s and O 1s BEs of molecularly adsorbed methanol, but the desorption barrier for mol. methanol desorption is not significantly influenced by the presence of Oad. A stable reaction intermediate, most probably methoxy (CH3Oad), was obsd. in the presence of Oad, between 160 and 220 K. It is an intermediate in the formation of both formate (HCO2ad) and COad, which occurs around 220 K. Formate decomps. around 350 K into CO2 (g) and Had (which reacts with the remaining oxygen to H2O), whereas the COad reacts with Oad around 400 K. [on SciFinder (R)

Ethanol adsorption, decomposition and oxidation on Ir(111) : a high resolution XPS study

Ethanol (C2H5OH) adsorption, decomposition and oxidation is studied on Ir(111) using high-energy resolution, fast XPS and temperature-programmed desorption. During heating of an adsorbed ethanol layer a part of the C2H5OHad desorbs molecularly, and another part remains on the surface and decomposes around 200 K; these two decomposition pathways are identified, as via acetyl (H3CCO) and via COad+CH3ad, respectively. Acetyl and CH3ad decompose around 300 K into CHad (and COad). CHad decomposes forming Cx and H2 around 520 K. In the presence of Oad an acetate intermediate is formed around 180 K, as well as a small amount of CH3ad and COad. Acetate decomposes between 400-480 K into CO2, H2(/H2O) and CHad

Benzene adsorption and oxidation on Ir(111)

Adsorption, decompn. and oxidn. of benzene on Ir(1 1 1) was studied by high resoln. (synchrotron) XPS, temp. programmed desorption and LEED. Mol. adsorption of benzene on Ir(1 1 1) is obsd. between 170 K and 350 K. Above this temp. both desorption and decompn. of benzene take place. An ordered adsorbate structure was obsd. upon adsorption around 335 K. Decompn. involves C-C bond breaking as the formation of CHad is obsd. The presence of a satd. Oad layer (0.5 ML) weakens mol. benzene adsorption and suppresses decompn. [on SciFinder (R)

dHvA oscillations and high-field magnetoresistance in U2Rh3Si5

We have observed dHvA oscillations (where H| a'-axis) in a single crystal of U<SUB>2</SUB>Rh<SUB>3</SUB>Si<SUB>5</SUB> below 1 K. The effective masses are found to be 5.3m<SUB>0</SUB> and 6.3m<SUB>0</SUB> for &#945; and &#946; branches, respectively. Large positive magnetoresistances are observed along the a', b-and c-axis with hystereses above 14.5 T, where the metamagnetic transition is observed along b in an earlier study. The low values of effective masses suggest a local moment on U and a postive magnetoresistance is consistent with antiferromagnetic ordering in this system