Rapid acceleration of the lower arm correlates with agonist EMGs during the initial phase

Fifty-eight healthy subjects made rapid elbow extensions to a target over 54 degrees. Angular acceleration was measured and surface electromyograms (EMGs) were recorded from the antagonistic muscles using monopolar rather than bipolar electrode configurations. Marked individual differences were found in the peak value of the first derivative of acceleration (dAcc/dt_Pk). The dAcc/dt_Pk correlated with both quantitative and qualitative properties of the agonist EMGs, but not with those of the antagonist EMG. The agonist EMGs, integrated until the moment of dAcc/dt_Pk, were positively correlated with dAcc/dt_Pk. The interval between EMG onset and EMG peak decreased with increasing dAcc/dt_Pk. The duration of the initial negative phase in the EMGs, which was considered to index the time required to recruit high-threshold MUs, decreased with increasing dAcc/dt_Pk. The results indicate that the ability to rapidly accelerate the lower arm varies across subjects, probably due in part to individual differences in the neural capacity to drive the agonists.     

Unilateral memory storage in the procerebrum of the terrestrial slug Limax

In most sensory modalities, neuronal inputs are bilaterally processed in a higher center. In some animal species, however, functional lateralization is sometimes observed in the sensory processing at the higher level. For the terrestrial slug Limax, olfaction is the most important sensory modality and this slug can acquire odor-aversion memories. Previously, it has been demonstrated in bilateral PC ablation experiments that the procerebrum (PC) is necessary for odor-aversion memory, and that the PC is the memory storage site. On the other hand, it has been hypothesized that only the unilateral PC is used for odor-aversion learning. Here we demonstrated that the number of the slugs with intact memory performance was reduced by approximately 50% when the PC was surgically ablated only unilaterally before or after conditioning. There was no difference in the memory performance of the right vs. the left PC-ablated slugs. However, memory deficit from unilateral PC ablation was not observed when the ipsilateral tentacles were also amputated at the same time. We also showed that there was no lateral memory transfer from one PC to the other, after up to 7 days post-conditioning. Our results demonstrated clearly that either the left or right PC is randomly used for olfactory learning, and that the side of use is determined at the level of the olfactory ascending pathway to the PC.     

Work Engagement in Japan: Validation of the Japanese Version of the Utrecht Work Engagement Scale

The purpose of this study was to validate the Japanese version of the Utrecht Work Engagement Scale (UWES‐J). Employees from three independent samples completed the questionnaire (total N= 2,334). Confirmatory factor analyses using the multiple‐group method revealed that, instead of the original three‐factor model, a one‐factor model that assumes that all engagement items load on one single factor fitted the data. Moreover, the one‐factor structure was invariant across all three samples. Internal consistency of the scale was sufficiently high (α= .92) and the test–retest reliability with an interval of two months was .66. A series of second‐order confirmatory factor analyses to examine construct validity confirmed the hypothesised model, indicating that work engagement was positively related to job satisfaction whereas it was negatively related to strain and burnout. However, as in previous studies, professional efficacy, a component of burnout, loaded on the engagement factor. These results, in general, suggest the reliability (internal consistency and stability), factorial invariance, and construct validity of the UWES‐J in three independent samples. Cette étude avait pour objectif de valider la version japonaise de l’Echelle d’Implication au Travail d’Utrecht (UWES‐J). 2,334 salariés provenant de trois échantillons indépendants ont rempli le questionnaire. Une analyse factorielle confirmatoire faisant appel à la méthode des groupes multiples a montré que le modèle originel en trois facteurs devait laisser la place à un modèle unifactoriel puisque tous les items d’implication étaient saturés sur un unique facteur qui rendait compte à lui seul des données. En outre, la structure monofactorielle restait identique à elle‐même sur les trois échantillons. La consistance interne de l’échelle était suffisamment élevée (α= .92) et la fidélité test‐retest après une période de deux mois était de .66. Une série d’analyses factorielles confirmatoires de second ordre destinées àétudier la validité de construction ont confirmé le modèle hypothétique, indiquant que l’implication dans le travail était en corrélation positive avec la satisfaction professionnelle tandis qu’elle était en relation négative avec la tension nerveuse et le burnout. Comme dans des travaux antérieurs, l’efficacité professionnelle, une composante du burnout, était saturée dans le facteur d’implication. Ces résultats, vont dans le sens de la fidélité (consistance interne et stabilité), de la solidité factorielle et de la validité de construction de l’UWES‐J dans ces trois échantillons indépendants.