1,721,462 research outputs found
The upstairs market for large block trades: An empirical analysis of price effects for italian shares
No full textUna analisi statistica multivariata di alcuni aspetti caratterizzanti la Rete di Lilliput
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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
L'informazione acustica come modello per l'esecuzione di gesti motori complessi: lo swing nel golf.
No full textIntroduzione. Nella letteratura, il timing viene descritto come una componente profonda dei programmi motori ed è un elemento fondamentale nella pianificazione dei movimenti volontari. C'è un generale accordo sull'influenza dell'informazione acustica sul timing nell'esecuzione di movimenti specifici. La stimolazione acustica è stata infatti spesso usata per standardizzare e migliorare la prestazione motoria. Il ritmo consente una rappresentazione mentale del timing dell’azione motoria ed è strettamente connesso all’esperienza motoria individuale dell’esecutore, individuando uno specifico modello di riferimento.
Nel presente studio si è indagata l'influenza dell'uso di modelli per il timing basati su diverse informazioni percettive sulla programmazione motoria di un gesto tecnico complesso quale lo swing nel golf.
Metodo. Si sono voluti confrontare gli effetti sulla prestazione in 3 condizioni di stimolazione: a. stimolazione uditiva associata con la migliore prestazione individuale (condizione acustica), b. stimolazione visiva associata con la migliore prestazione individuale (condizione visiva) e c. assenza di stimolazione (condizione di controllo). 12 golfisti esperti hanno partecipato allo studio, tutti sono stati sottoposti alle 3 condizioni in ordine controbilanciato prima dell'esecuzione del gesto.
Risultati. La condizione acustica porta a una prestazione migliore rispetto alle altre 2 condizioni. Il modello acustico migliora la capacità dei golfisti di arrivare vicino alla buca e riduce drasticamente la variabilità nella lunghezza dei tiri.
Conclusioni. L'informazione acustica fornisce il timing per riprodurre un programma motorio con caratteristiche simili al modello di riferimento, migliorando così la prestazione. Da un punto di vista applicativo i risultati emersi indicano possibili sviluppi di metodologie semplici ed efficaci per l'apprendimento e per il miglioramento del gesto tecnico nel golf
Golf swing sound recognition: The role of timing
No full textIn the field literature it can be found that acoustic information can affect both the relative timing (RT) and the overall duration (OD) of voluntary movements. This suggests that sound can provide a mental temporal motor representation of movement. Aim of this work was to investigate whether golfers are able to discriminate between the sounds associated to their own from other golfers' swings. The sounds produced by the participants performing 65 m shots have been recorded and used to create 5 stimuli, in which RT and OD have been manipulated. The experimental conditions were: participant's swing sound, other golfers' sounds having equal both RT and OD, equal RT but different OD, different RT but equal OD, and both different RT and OD. Task of the participants was to say whether each sound corresponded or not to their own swing. Results show that golfers are able to recognize their own movements, but they also recognize as their own the sound produced by other athletes having equal both RT and OD. These conditions are significantly different from the other ones. This suggest that temporal features are quite relevant in sound recognition, but they are not the only information provided by the sound
A Sound Up-to- n, δ Bisimilarity for PCTL
No full textWe tackle the problem of establishing the soundness of approximate bisimilarity with respect to PCTL and its relaxed semantics. To this purpose, we consider a notion of bisimilarity similar to the one introduced by Desharnais, Laviolette, and Tracol, which is parametric with respect to an approximation error δ, and to the depth n of the observation along traces. Essentially, our soundness theorem establishes that, when a state q satisfies a given formula up-to error δ and steps n, and q is bisimilar to q′ up-to error δ′ and enough steps, we prove that q′ also satisfies the formula up-to a suitable error δ′ ′ and steps n. The new error δ′ ′ is computed from δ, δ′ and the formula, and only depends linearly on n. We provide a detailed overview of our soundness proof
The role of timing in recognising own motor actions through sound information.
No full textIn the literature it can be found that acoustic information can influence motor performance. This suggests that sound can provide a mental temporal motor representation of the movement itself. Voluntary movements can be decomposed in the relative timing component and the overall duration component. Movement recognition is an important aspect in both daily life and sport activities. The present work was aimed to investigate whether golfers are able to discriminate between the sounds associated to their own from other golfers' swings. The main goal of the experiment was to study the role of the temporal structure of the stimuli. Participants were provided with acoustic cues produced during the swing. A manipulation of movements overall duration and relative timing was applied to others’ tracks, leading to the creation of five stimuli, corresponding to five experimental conditions: participant's swing sound, other golfers' sounds having equal both relative timing and overall duration, other golfers' sounds having equal relative timing but different overall duration, other golfers' sounds having different relative timing but equal overall duration, and other golfers' sounds having both different relative timing and overall duration. The task of the participants was to say whether each sound corresponded or not to their own swing. Results show that participants were able to identify their own movements, and wrongly recognize others’ tracks as their own, when both overall duration and relative timing were equal to individual sounds. These conditions are significantly different from the other ones. This suggests that the temporal features are quite relevant in the sound recognition of a motor action, but they are not the only information provided by the sound. Therefore, these findings provide further evidence to the relevance of timing for auditory movement recognition and are consistent with recent Gestalt interpretations of motor control
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