1,721,098 research outputs found
EFFECTS OF TRAINING REGIMES AT DIFFERENT INTENSITIES ON PERFORMANCE AND OXIDATIVE STRESS IN MASTERS ATHLETES
Full text linkOver the last decade, the participation of middle-aged and older (‘masters’) involved in sport activities at different levels has significantly increased, particularly in long-distance events. Master athletes are typically characterized as people who continue physical training throughout life and in this population, the incidence and risk of chronic and age-related diseases are reportedly lower, and self-rated health is better than in apparently healthy controls. However, regardless of training a decline in peak athletic performance in both endurance and sprint events and for all competitions/disciplines usually occurs with aging. In particular, declines in endurance exercise performance and its physiological determinants with ageing appear to be mediated in large part by a reduction in the exercise training ‘stimulus’, mainly as a result of increased work and family commitments, few masters still follow structured training programs, and the increased prevalence of exercise training-associated injuries that probably contributes to their reduced training intensity and volume. Furthermore, aging is accompanied by a progressive increase in free radical production (i.e., synthesis of reactive oxygen species) with a concomitant decrease in the enzymatic defence mechanisms, promoting the development of oxidative stress. The chronic repetition of exercise, i.e. exercise training, may have the capability to develop a compensation to oxidative stress in skeletal muscle fibres by means of an adaptation of the antioxidant and repair systems. This might result in a decreased resting level of oxidative damage and an increased resistance to oxidative stress.
In general, the main types of training used to improve endurance exercise performance are: i) continuous training at moderate intensity (CON); and ii) discontinuous training at high intensity (DHIT). Different studies showed that even in sedentary or moderately trained individuals, DHIT might be an efficient strategy to induce adaptations in skeletal muscle and exercise performance that are comparable with conventional endurance training. The first part of the thesis is focus on master runners. First study aims to evaluate if an individualized training schedules characterized by an overall reduction of training volume is able to improve running performance. Moreover, the impact of CON and DHIT training programs on running performance and its main physiological factors in master runners has been evaluated. The second study aims to evaluate the effects of 8-week of DHIT and CON on resting level and time-course changes of several indexes of oxidative stress. The main findings of these studies show that despite a significant reduction of training volume, CON and DHIT, characterized by the same total volume, improve running economy and running performance. Furthermore, both CON and DHIT induced similar beneficial effects, reducing the resting levels of oxidative stress biomarkers in plasma and urine. The second part of the thesis is focused on master swimmers. The third study aims to compare the effects of two opposite training protocols (low-volume high-intensity vs high-volume low-intensity) in a group of trained master swimmers. The fourth study aims to examine the effects of low-volume high-intensity training on ROS production and on antioxidant capacity in master swimmers by applying electron paramagnetic resonance measurement. The results indicate that in master swimmers an increase of training volume may lead to an improvement of indexes of aerobic capacity and middle-long distance performance. A subsequent period of high-intensity low-volume training, besides maintaining previous improvements, may positively affect also short distance performance. Moreover, high intensity training improves antioxidant capacity and significantly decreases baseline ROS production
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
An application of the Self Organizing Map algorithm to computer aided classification of Aster Multispectral data
No full textIn this paper we employ the Kohonen's Self Organizing Map (SOM) as a strategy for an unsupervised analysis of ASTER multispectral (MS) images. In order to obtain an accurate clusterization we introduce as input for the network, in addition to spectral data, some texture measures extracted from IKONOS images, which gives a contribution to the classification of manmade structures. After clustering of SOM outcomes, we associated each cluster with a major land cover and compared them with prior knowledge of the scene analyzed
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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