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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
Metabolic and cardiorespiratory responses to maximal intermittent knee isokinetic exercise in young healthy humans
No full textThere have been many studies on the effects of isokinetic exercise on muscle performance in training and rehabilitative programmes. On the other hand, the cardiovascular and metabolic responses elicited by this type of exercise have been poorly investigated. This study was specifically designed to describe the relationships, if any, between metabolic and cardiorespiratory responses and power output during maximal intermittent knee isokinetic exercise when a steady state is reached. A group of 18 healthy subjects (10 men and 8 women, age range 25-30 years) were requested to perform at maximal concentric isokinetic knee extensions/flexions 60°·s-1 and 180°·s-1 for 5 min, with a 5-s pause interposed between consecutive repetitions. The power output (Ẇ) was calculated; before and during the tasks heart rate (f(c)) and arterial blood pressure (AP(a)) were continuously monitored. Pulmonary ventilation V̇(E) and oxygen uptake (V̇O2) were measured at the 4th and at the 5th min of exercise and blood lactate concentration at rest and at the 3rd min of recovery. From the 4th to the 5th min only a slight decrease in Ẇ was observed, both at 60°·s-1 and 180°·s-1. The V̇2, V̇(E), f(c) and AP(a) showed similar values in the last 2 min of exercise, suggesting that a steady state had been reached. The V̇O2 increased linearly as a function of Ẇ, showing a significantly steeper slope at 60°·s-1 than at 180°·s-1. The f(c), in spite of a large interindividual variation, was linearly related to metabolic demand, and was not affected by angular velocity. Systolic and diastolic AP(a) were not related either to V̇O2 or to angular velocity. In conclusion it would appear that the metabolic response to maximal intermittent knee isokinetic exercise resembles that of dynamic exercise. Conversely, the cardiocirculatory responses would seem to reflect a relevant role of the isometric postural component, the importance of which should be carefully evaluated in each subject
Effetti dell'allenamento isocinetico sulla risposta cardiocircolatoria del soggetto anziano
No full textThe maximal oxygen uptake (VO 2max) is commonly used for assessing the individual aerobic fitness. Many studies have shown in elderly subjects that an increase in cardiorespiratory function and VO 2max can be achieved with endurance training, but the effects of strength conditioning on cardiovascular fitness and aerobic power have not been extensively examined in older subjects. The lack of data concerning the effects of isokinetic training on cardiopulmonary function in elderly subjects has prompted the present study. Eight sedentary men (average 68 ± 4 years) underwent 13 weeks of isokinetic training, two sessions per week lasting one hour each. One week before and two-three days after the training period each subject performed: A) isokinetic strength test evaluating the knee extensor and flexor muscles; B) incremental exercise on a bicycle ergometer up to voluntary exhaustion. In addition, measurement of quadriceps cross-sectional area (CSA) was carried out by means of nuclear magnetic resonance imaging. At all investigated angular velocities there was, after training, a significant (p < 0.05) increase of both extensor and flexor muscles isokinetic strength. After training all investigated subjects showed during exercise B) lower values of heart rate (HR) both at rest and at the same absolute workload. The average value of maximal oxygen consumption (VO 2 peak) increased from 24.9 to 27.6 ml·min -1·kg -1 (p < 0.01). A linear relationship (p < 0.05) was found between VO 2 peak and CSA values obtained both before and after training. The results of the present study have shown that, at least in our limited group of sedentary elderly men, isokinetic strength training program besides improve muscle mass and strenght may also increase maximal aerobic power. Furthermore this latter resulted close correlated with the quadriceps CSA value, supporting a causal role for peripheral factors in determining VO 2 peak. From these findings it appears beneficial for elderly population to add to traditional aerobic rehabilitation/training protocols, a series of isokinetic exercises
New methods of functional evaluation of patients with metabolic myopathies : the effects of exercise training
No full textINTRODUCTION
Mitochondrial myopathies (MM) and myophosphorylase deficiency (McArdle’s disease, McA) are genetic disorders characterized by impairments of energy metabolism which translate into reduced exercise tolerance. At present the therapeutic interventions available for these patients are very limited. Evidence has been provided that aerobic training should be considered as a treatment for these
conditions. Aim of the present study was to utilize non−invasive methods of functional evaluation, specifically aimed at oxidative metabolism at the skeletal muscle level, in order to evaluate the effects of an aerobic exercise training.
METHODS
7 MM and 8 McA patients underwent 12 weeks of exercise training (4v/weeks) at home at an heart rate (HR) corresponding to about 65-70% of the maximal HR. Oxygen uptake (V’O2) and skeletal muscle (vastus lateralis) fractional O2 extraction (by NIRS) were assessed during incremental and moderate and high-intensity constant-load exercises: All tests were carried out on a cycle
ergometer before (BEFORE) and at the end (AFTER) of the training period. Before and about 2 months after the termination of the training period average daily energy expenditure (EE) of the patients were determinated (SenseWear Armband).
RESULTS
V’O2peak increased significantly with training both in MM (from 14.7 ± 3.0 [x ± SD] mL/kg/min BEFORE to 17.6 ± 3.3 AFTER) and in McA (from 17.4 ± 4.0 mL/kg/min to 20.4 ± 4.4 mL/kg/min). Peak skeletal muscle (vastus lateralis) fractional O2 extraction increased with training both in MM (from 22.0 ± 16.5 % to 32.6 ± 14.5) and in McA (from 17.8 ± 17.9 % to 43.4 ± 17.4). During the high-intensity
constant-load exercise, MM and McA patients showed, after training, clear signs of increased exercise tolerance, such as lower HR (from 134.3 ± 26.6 b/min to 121.2 ± 21.9) and lower scores at the Borg’s scale of perceived exertion (from 14.5 ± 1.2 to 12.3 ± 1.5). EE was not different BEFORE (36.6 ± 9.2 kcal/day/kg) vs. AFTER (35.7 ± 13.4).
CONCLUSION
In MM and McA patients a 12 weeks aerobic training program significantly increased exercise tolerance. Our findings confirm that near infrared spectroscopy can effectively detect the functional improvements obtained by training, yielding insights also on the mechanisms of the improvements at the pathophysiological level. Surprisingly, the improvements in exercise tolerance obtained by
the training program did not determine an increase in average daily energy expenditure
Metabolic and circulatory responses to an isokinetic protocol
No full textThe metabolic demand and the cardiorespiratory responses to isokinetic rehabilitation protocol have been studied in 11 females (F) and 11 males (M; age: 25-30 years). The exercise consisted in 3 series of 5 maximal concentric knee extensions/flexions at 180, 120, 90, 120, 180°/s, with a 40 s pause between each series (total duration about 15 min). The work (extensors plus flexors) was determined; V̇E and V̇O2 were measured on a breath-by-breath basis. HR was continuously recorded and arterial pressure (AP) was measured during each pause. It resulted that: i) the work at 180°/s was 1170±400 J (mean±SD) in F and 1670±350 J in M, then changing according to the angular velocities (mean increase at 90°/s: 18% in F and 34% in M); ii) V̇O2, V̇E and HR increased in an exponential-like fashion, reaching constant values after about 2.5-3.5 min of exercise. V̇O2 was 0.8±0.2 L/min and 1.3±0.3 L/min, V̇E 30±6 L/min and 45±15 L/min and HR 153±13 b/min and 145±15 b/min in F and M, respectively; iii) systolic AP increased of about 20 mmHg for the entire exercise, while diastolic pressure was unchanged. Even if the exercise was intermittent, metabolic and cardiocirculatory steady states were reached, which indicate that the maximal isokinetic protocol of this study is comparable to a dynamic exercise of medium-high intensity
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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