Variation of the Jovian Magnetopause Under Constant Solar Wind Conditions: Significance of Magnetodisc Dynamics

It is generally believed that variations in the upstream solar wind (SW) and interplanetary magnetic field (IMF) conditions are the main cause of changes of Jupiter's magnetopause (JM) location. However, most previous pressure balance models for the JM are axisymmetric and do not consider internal drivers, for example, the dynamics of the magnetodisc. We use three-dimensional global magnetosphere simulations to investigate the variation of the JM under constant SW/IMF conditions. These simulations show that even without variations in the upstream driving conditions, the JM can exhibit dynamic variations, suggesting a range as large as 50 Jupiter radii in the subsolar location. Our study shows that the interchange structures in the Jovian magnetodisc will introduce significant radial dynamic pressure, which can drive significant variation in the JM location. The results provide important new context for interpreting the JM location and dynamics, with key implications for other internally mass-loaded and/or rapidly rotating systems

Controlling a robotic hip exoskeleton with noncontact capacitive sensors

For partial lower-limb exoskeletons, an accurate real-time estimation of the gait phase is paramount to provide timely and well-tailored assistance during gait. To this end, dedicated wearable sensors separate from the exoskeletons mechanical structure may be preferable because they are typically isolated from movement artifacts that often result from the transient dynamics of the physical human-robot interaction. Moreover, wearable sensors that do not require time-consuming calibration procedures are more easily acceptable by users. In this study a robotic hip orthosis was controlled using capacitive sensors placed in orthopedic cuffs on the shanks. The capacitive signals are zeroed after donning the cuffs and do not require any further calibration. The capacitive sensing-based controller was designed to perform online estimation of the gait cycle phase via adaptive oscillators, and to provide a phase-locked assistive torque. Two experimental activities were carried out to validate the effectiveness of the proposed control strategy. Experiments conducted with seven healthy subjects walking on a treadmill at different speeds demonstrated that the controller can estimate the gait phase with an average error of 4%, while also providing hip flexion assistance. Moreover, experiments carried out with four healthy subjects showed that the capacitive sensing-based controller could reduce the metabolic expenditure of subjects compared to the unassisted condition (mean ± SEM, -3.2% ± 1.1)

Rapid biotic rebound during the late Griesbachian indicates heterogeneous recovery patterns after the Permian-Triassic mass extinction

New fossil data from two Early Triassic (Griesbachian to Dienerian) sections from South China show unusually high levels of both benthic and nektonic taxonomic richness occurring in the late Griesbachian. In total, 68 species (including 26 newly originated species) representing mollusks, brachiopods, foraminifers, conodonts, ostracods, and echinoderms occur in the late Griesbachian, indicating well-established and relatively complex marine communities. Furthermore, the nekton shows higher origination rates than the benthos. Analyses of the sedimentary facies and size distribution of pyrite framboids show that this high-diversity interval is associated with well-oxygenated environments. In contrast to the previously suggested scenario, which inferred that persistently harsh environmental conditions impeded the biotic recovery during the Early Triassic, our new findings, combined with recent work, indicate a fitful regional recovery pattern after the Permian-Triassic crisis, resulting in three main diversity highs: late Griesbachian–early Dienerian, early–middle Smithian, and Spathian. The transient rebound episodes were therefore influenced by both extrinsic local (e.g., redox condition, temperature) and intrinsic (e.g., biological tolerances, origination rates) parameters

Lexical inferencing in reading comprehension and subsequent vocabulary acquisition in Chinese as a foreign language

Nous nous intéressons à l’utilisation de l’inférence lexicale en langue seconde/étrangère (L2) qui consiste en la déduction du sens d’un mot inconnu rencontré dans la lecture. Nous cherchions à savoir 1) si l’existence d’un équivalent lexical dans la langue maternelle de l’apprenant pour un mot L2, ou la lexicalisation, influence l’inférence et l’acquisition subséquente de ce mot et 2) si une charge cognitive plus importante dans l’input aboutit à de meilleurs gains lexicaux pour ce mot.Selon les résultats de notre étude menée auprès d’apprenants francophones ayant un niveau intermédiaire en chinois, la lexicalisation n’a pas d’effet sur l’attention que les apprenants portent aux mots inconnus pendant la lecture, mais elle influence le choix de sources de connaissance des apprenants pendant l’inférence lexicale ; la lexicalisation n’est pas l’élément concluant dans le résultat de l’inférence lexicale, cependant, les apprenants ont davantage de difficultés à retenir les mots non lexicalisés à court et à long terme ; enfin, la combinaison de deux tâches post-inférence aboutit à de meilleurs gains pour les mots inconnus sur le plan formel.We are interested in lexical inferencing in a second/foreign language (L2) which consists in deducing the meaning of an unknown L2 word encountered in reading. We investigated 1) whether the existence of a lexical equivalent in learner's native language for an L2 word, or the lexicalization, influences the inferencing and subsequent acquisition of that word and 2) whether a more important cognitive load in the input results in better lexical gains for that word.According to the results of our study of French-speaking learners with an intermediate level in Chinese, with no effect on learner’s attention to unfamiliar words during reading, lexicalization influences learner’s choice of knowledge sources during lexical inferencing; lexicalization is not the conclusive factor in the result of lexical inferencing, but learner has more difficulty retaining the meaning of unlexicalized L2 words in both the short and long terms.; finally, the combination of two post-inference tasks leads to better gains for unknown words, especially on the formal level

Inférence lexicale dans la compréhension écrite et acquisition subséquente du vocabulaire en chinois langue étrangère

We are interested in lexical inferencing in a second/foreign language (L2) which consists in deducing the meaning of an unknown L2 word encountered in reading. We investigated 1) whether the existence of a lexical equivalent in learner's native language for an L2 word, or the lexicalization, influences the inferencing and subsequent acquisition of that word and 2) whether a more important cognitive load in the input results in better lexical gains for that word.According to the results of our study of French-speaking learners with an intermediate level in Chinese, with no effect on learner’s attention to unfamiliar words during reading, lexicalization influences learner’s choice of knowledge sources during lexical inferencing; lexicalization is not the conclusive factor in the result of lexical inferencing, but learner has more difficulty retaining the meaning of unlexicalized L2 words in both the short and long terms.; finally, the combination of two post-inference tasks leads to better gains for unknown words, especially on the formal level.Nous nous intéressons à l’utilisation de l’inférence lexicale en langue seconde/étrangère (L2) qui consiste en la déduction du sens d’un mot inconnu rencontré dans la lecture. Nous cherchions à savoir 1) si l’existence d’un équivalent lexical dans la langue maternelle de l’apprenant pour un mot L2, ou la lexicalisation, influence l’inférence et l’acquisition subséquente de ce mot et 2) si une charge cognitive plus importante dans l’input aboutit à de meilleurs gains lexicaux pour ce mot.Selon les résultats de notre étude menée auprès d’apprenants francophones ayant un niveau intermédiaire en chinois, la lexicalisation n’a pas d’effet sur l’attention que les apprenants portent aux mots inconnus pendant la lecture, mais elle influence le choix de sources de connaissance des apprenants pendant l’inférence lexicale ; la lexicalisation n’est pas l’élément concluant dans le résultat de l’inférence lexicale, cependant, les apprenants ont davantage de difficultés à retenir les mots non lexicalisés à court et à long terme ; enfin, la combinaison de deux tâches post-inférence aboutit à de meilleurs gains pour les mots inconnus sur le plan formel

Inférence lexicale dans la compréhension écrite et acquisition subséquente du vocabulaire en chinois langue étrangère

We are interested in lexical inferencing in a second/foreign language (L2) which consists in deducing the meaning of an unknown L2 word encountered in reading. We investigated 1) whether the existence of a lexical equivalent in learner's native language for an L2 word, or the lexicalization, influences the inferencing and subsequent acquisition of that word and 2) whether a more important cognitive load in the input results in better lexical gains for that word.According to the results of our study of French-speaking learners with an intermediate level in Chinese, with no effect on learner’s attention to unfamiliar words during reading, lexicalization influences learner’s choice of knowledge sources during lexical inferencing; lexicalization is not the conclusive factor in the result of lexical inferencing, but learner has more difficulty retaining the meaning of unlexicalized L2 words in both the short and long terms.; finally, the combination of two post-inference tasks leads to better gains for unknown words, especially on the formal level.Nous nous intéressons à l’utilisation de l’inférence lexicale en langue seconde/étrangère (L2) qui consiste en la déduction du sens d’un mot inconnu rencontré dans la lecture. Nous cherchions à savoir 1) si l’existence d’un équivalent lexical dans la langue maternelle de l’apprenant pour un mot L2, ou la lexicalisation, influence l’inférence et l’acquisition subséquente de ce mot et 2) si une charge cognitive plus importante dans l’input aboutit à de meilleurs gains lexicaux pour ce mot.Selon les résultats de notre étude menée auprès d’apprenants francophones ayant un niveau intermédiaire en chinois, la lexicalisation n’a pas d’effet sur l’attention que les apprenants portent aux mots inconnus pendant la lecture, mais elle influence le choix de sources de connaissance des apprenants pendant l’inférence lexicale ; la lexicalisation n’est pas l’élément concluant dans le résultat de l’inférence lexicale, cependant, les apprenants ont davantage de difficultés à retenir les mots non lexicalisés à court et à long terme ; enfin, la combinaison de deux tâches post-inférence aboutit à de meilleurs gains pour les mots inconnus sur le plan formel

Inférence et apprentissage du vocabulaire : effet de la lexicalisation en première langue et de la tâche

International audienceLexical inferencing is an important strategy in reading comprehension and vocabulary learning, both in L2 and in L1. Focusing both on the effect of L1 lexicalization (i.e., the existence of lexical equivalents in learner’s L1 for a L2 word) and on that of learner’s cognitive investment, we are interested in the process of inferring an unknown L2 word encountered in reading and the subsequent learning of the inferred word. We observed 33 French-speaking learners of Chinese while they inferred 20 unknown Chinese words contained in two passages and examined the evolution of their lexical knowledge of these words. The results show that the L1 lexicalization is not a critical factor for French-speaking learners to understand an unknown Chinese word. However, it is more difficult for them to retain the meaning of a non-lexicalized Chinese word than a lexicalized one, in the short and long term. Moreover, a more important cognitive involvement may help a learner obtain a better grasp of an unknown word, but only of its form, not its meaning.L’inférence lexicale est une importante stratégie de lecture et d’apprentissage du vocabulaire, en L2 comme en L1. Nous nous intéressons à l’utilisation de cette stratégie en L2 afin de déduire le sens d’un mot inconnu pendant la lecture et l’apprentissage subséquent du mot inféré, en nous penchant sur l’effet de la lexicalisation (c’est-à-dire l’existence ou pas d’une unité lexicale équivalente attestée dans la L1 de l’apprenant pour un mot donné de la L2) et l’effet de l’investissement cognitif de l’apprenant sur le mot inconnu. Nous avons observé 33 apprenants francophones du chinois L2 lorsqu’ils infèrent 20 mots chinois inconnus intégrés dans deux textes et avons examiné l’évolution des connaissances lexicales des participants pour les mots cibles. Nos résultats montrent que la nature de la lexicalisation d’un mot chinois inconnu n’est pas le facteur concluant dans la compréhension du mot chez les apprenants francophones. Ces derniers ont pourtant plus de difficultés à retenir le sens d’un mot chinois non lexicalisé qu’un mot lexicalisé, à court et à long terme. Nos résultats montrent également qu’un investissement cognitif plus important des apprenants sur un mot inconnu peut favoriser l’apprentissage du mot sur le plan formel mais non sur le plan sémantique

Gait phase detection based on non-contact capacitive sensing: Preliminary results

Gait phase detection is essential to the control of lower-limb exoskeletons. In this paper, we present a non-contact capacitive sensing strategy for gait phase detection to replace foot pressure sensors. The designed capacitance sensing system can record signals of human muscle contraction from the leg. The electrodes are non-contact with the skin, which are fixed on the particularly designed cuffs. To evaluate the performance of the capacitance sensing on gait phase detection, two experiments are conducted on healthy subjects. With selected features and sliding window classification method, the proposed method obtains 98.3% average accuracy with the sensing cuff on the shank and 96.5% accuracy with the sensing cuff on the thigh for level walking tasks. The system also accurately recognizes the gait events (largest error rate smaller than 0.6%) when walking speed changes. The preliminary results indicate that the proposed sensing strategy is a promising solution to provide useful gait information for exoskeleton control

A Locomotion Intent Prediction System Based on Multi-Sensor Fusion

Locomotion intent prediction is essential for the control of powered lower-limb prostheses to realize smooth locomotion transitions. In this research, we develop a multi-sensor fusion based locomotion intent prediction system, which can recognize current locomotion mode and detect locomotion transitions in advance. Seven able-bodied subjects were recruited for this research. Signals from two foot pressure insoles and three inertial measurement units (one on the thigh, one on the shank and the other on the foot) are measured. A two-level recognition strategy is used for the recognition with linear discriminate classifier. Six kinds of locomotion modes and ten kinds of locomotion transitions are tested in this study. Recognition accuracy during steady locomotion periods (i.e., no locomotion transitions) is 99.71% ± 0.05% for seven able-bodied subjects. During locomotion transition periods, all the transitions are correctly detected and most of them can be detected before transiting to new locomotion modes. No significant deterioration in recognition performance is observed in the following five hours after the system is trained, and small number of experiment trials are required to train reliable classifiers