1,720,963 research outputs found
An educational experience with motor planning and sound semantics in virtual audio reality
No full textThis paper reports an educational experience with 75 graduate students on action preparation as a function of sound semantics. In 6 hours of lesson and by working in groups, students are able to investigate modulations in motor preparation timing induced by sounds that fall within their peri-personal space (PPS) in non-visual virtual reality setting. The proposed protocol is designed so as students can learn by doing and analyze human motor planning of a simple action in reaction to approaching-looming sound sources rendered via headphones. The interesting aspect here is that we give students the opportunity to directly experience the close connection between sound and movement; in particular, auditory perception stimulated by sounds conveying different emotional contents, is modulated within the individual PPS in terms of action anticipation and distance perception
Leverage mechanical alterations during walking at self-selected speed in patients with Parkinson's disease
No full textIndividuals with Parkinson's disease (PD) show poor walking performance compared to healthy adults. Leverage changes may provide insight into this walking abnormality, since they have important effects on both biomechanical and physiological variables. Hence, we investigated the differences in internal and external moment arms at the knee and ankle joints, as well as the effective mechanical advantage during walking at self-selected speed. Furthermore, the effects on walking of a simultaneous cognitive task were analysed. Kinetic (resultant ground reaction force and joint moments), kinematic (movement speed) and mechanical leverage (internal and external moment arms) parameters of 10 mild-to-moderate PD patients and 10 age-matched controls were measured in single and dual task condition. Finally, effective mechanical advantage was calculated as the ratio between internal and external moment arm for each joint. PD patients had a slower walking and showed larger and lower values of knee and ankle joint moments, respectively. No difference in force among groups was recorded. External moment arms were larger (in both joints) for PD, whereas slight changes were observed for internal moment arms. Consequently, effective mechanical advantage values seemed to be lower for PD. Surprisingly, leverage difference among groups was reduced during the dual task condition, resulting in a "more effective" walking strategy for PD. These findings suggest that during single task PD patients have several leverage disadvantages, which could affect the joint assessment. On the contrary, during dual task they reduced these mechanical negative effects by positively obtaining normal values of effective mechanical advantage
Effetti di età e genere sull’efficienza propulsiva nello stile libero
No full textLa performance nel nuoto (la massima velocità di nuoto) è influenzata sia da fattori fisiologici che da fattori biomeccanici. Molti hanno studiato gli effetti di età e genere sui fattori fisiologici, ma ancora poco è noto riguardo ai fattori biomeccanici. In questo studio, abbiamo misurato/calcolato i seguenti parametri: frequenza di bracciata (SF), lunghezza di bracciata (SL) ed efficienza propulsiva (Ep) in maschi (M) e femmine (F) di diverse età (N = 185, 7÷75 anni) a sei diverse velocità di nuoto (da lenta a massimale). I risultati riportati in questo studio confermano ed estendono precedenti conclusioni: 1) SF è maggiore nei bambini che negli adulti ed è più alta nei maschi che nelle femmine; essa diminuisce linearmente in funzione dell’età; 2) SL ed Ep sono maggiori negli adulti rispetto ai bambini; nell’età adulta tendono a diminuire dopo i 50 anni; le differenze legate al genere sono minori di quelle osservate per la SF; 3) nell’infanzia e nell’adolescenza, la curva che mette in relazione velocità ed SF si “muove verso l’alto” così come avviene durante allenamento (questo “shift” avviene temporalmente prima nelle femmine che nei maschi); dopo i 50 anni, questa curva si “muove verso il basso” così come avviene nel de-training. Parole chiave: Nuoto; Età; Differenze di genere; Frequenza di bracciata; Ampiezza di bracciata; Efficienza propulsiva
Analisi comparativa del comportamento posturale e muscolare in soggetti con corsetto ortopedico
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
The effect of a secondary task on kinematics during turning in Parkinson's disease with mild to moderate impairment
Full text linkPatients with Parkinson's disease (PD) show typical gait asymmetries. These peculiar motor impairments are exacerbated by added cognitive and/or mechanical loading. However, there is scarce literature that chains these two stimuli. The aim of this study was to investigate the combined effects of a dual task (cognitive task) and turning (mechanical task) on the spatiotemporal parameters in mild to moderate PD. Participants (nine patients with PD and nine controls (CRs)) were evaluated while walking at their self-selected pace without a secondary task (single task), and while repeating the days of the week backwards (dual task) along a straight direction and a 60 degrees and 120 degrees turn. As speculated, in single tasking, PD patients preferred to walk with a shorter stride length (p< 0.05) but similar timing parameters, compared to the CR group; in dual tasking, both groups walked slower with shorter strides. As the turn angle increased, the speed will be reduced (p< 0.001), whereas the ground-foot contact will become greater (p< 0.001) in all the participants. We showed that the combination of a simple cognitive task and a mechanical task (especially at larger angles) could represent an important training stimulus in PD at the early stages of the pathology
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