1,721,215 research outputs found
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
Movements not involved in posture are abnormal in Parkinson's disease
No full textWe have studied movements of the top joint of the thumb in a group of patients with Parkinson's disease. Even when movements were performed with the proximal phalanx of the thumb clamped, and with the forearm fully supported, movement time was prolonged and multiple bursts of EMG activity were present in the flexor pollicis longus. An abnormality of such movements performed with complete external postural support suggests that disease of the basal ganglia affect all movements, not just those involved in posture. © 1984
THE CORNEAL REFLEX AND THE R2 COMPONENT OF THE BLINK REFLEX
No full textA reflex contraction of the human orbicularis oculi muscles can be evoked by stimulation of either the supraorbital region ('blink reflex') or the cornea ('corneal reflex'). We found that the latency of the corneal reflex was longer, and the duration was longer than the R2 component of the blink reflex. The absolute refractory period of the R2 component of the blink reflex was longer after supraorbital than after corneal conditioning stimulation. When the R2 component of the blink reflex was habituated by repetitive stimuli, stimulation of the cornea still evoked a reflex, but supraorbital stimulation produced only a depressed R2 response. These findings suggest that the two reflexes do not have identical neural connections
Reciprocal inhibition between muscles of the human forearm in normal subjects and in patients with idiopathic torsion dystonia.
No full text[No abstract available
PHYSIOLOGICAL ANALYSIS OF SIMPLE RAPID MOVEMENTS IN PATIENTS WITH CEREBELLAR DEFICITS
No full textPatients with cerebellar deficits made elbow flexion movements as rapidly as possible for three different angular distances. Electromyographic activity of biceps and triceps and the kinematics of the movements were analysed. Results were compared with those of normal subjects making both rapid and slow movements. In the patients, the first agonist burst of the biceps was frequently prolonged regardless of the distance or speed of the movement. The most striking kinematic abnormality was prolonged acceleration time. The pattern of acceleration time exceeding deceleration time was common in patients but uncommon in normal subjects. The best kinematic correlate of the duration of the first agonist burst was acceleration time. Altered production of appropriate acceleration may therefore be an important abnormality in cerebellar dysfunction for attempted rapid voluntary movements
Duration of the first agonist EMG burst in ballistic arm movements
No full textIn normal subjects, fast arm movements are accomplished by a diphasic or triphasic EMG activation of the agonist and antagonist muscle. The duration of the first agonist burst (Ag1) has been said to be constant for movements of different size, whilst its amplitude is variable. Previous studies focused on relatively small movements (10-40°). We have studied the behaviour of the Ag1 duration over the full physiological range of wrist and elbow flexion movements in normal subjects. The results showed that the principle of invariance of Ag1 duration was true when small movements of about 15-30° were studied, but when larger movements were made burst length increased. A similar increase in Ag1 burst duration also was seen during movements performed againts a load and in contractions made with fatiqued muscles. Changes in duration of the Ag1 burst appear to be part of the normal mechanism for increasing the impulsive force provided in rapid contractions. © 1984
Scaling of the size of the first agonist EMG burst during rapid wrist movements in patients with Parkinson's disease
No full textRapid wrist flexion movements were studied in a group of 10 patients with Parkinson's disease both on and off their normal drug therapy, and were compared with the same movements made by a group of eight normal individuals. When normal subjects made movements through 60°, the first agonist burst of EMG activity in the wrist flexor muscles was longer and larger than that seen in movements of 15°. If a large opposing load of 2.2 Nm was added, this also increased the size and duration of the first agonist EMG burst. Although the movements made by the patients were slower than those of normals, the size and duration of the first agonist EMG burst changed with movement size and added load in the normal way. This shows that patients can produce large, long bursts of EMG activity, but that there is a failure to match these parameters appropriately to the size of movement required. The effect of levodopa therapy on the movements was not dramatic. Although patients produced faster wrist movements when on medication than when off, the change was relatively small compared with the change seen in their overall clinical rating. Changes in the velocity of movements at a single joint are not a good reflection of the overall clinical state of patients with Parkinson's disease
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
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