1,720,987 research outputs found
Il costo energetico di varie forme di locomozione umana : implicazioni teoriche e pratiche
Full text linkLo scopo principale della tesi di dottorato è stato quello di studiare il costo energetico di varie forme di locomozione umana in diverse condizioni sperimentali. Nella fattispecie, le forme di locomozione e le condizioni sperimentali studiate, sono state:
I. la corsa in linea ed a navetta, con metodica continua ed intermittente;
II. la corsa a navetta intermittente con cambi di senso normali o rapidi, e gli effetti di 5 settimane di allenamento, sul costo energetico della corsa in linea ed a navetta intermittente;
III. la corsa in linea ed a navetta intermittente in calciatori professionisti prima e dopo un periodo di allenamento;
IV. lo yo-yo endurance test ed il costo energetico della corsa in linea in calciatori professionisti (serie C1) prima dopo sei mesi di allenamento e gare;
V. la corsa in linea ed a navetta : differenza tra calciatori professionisti e maratoneti amatori di buon livello;
VI. il cammino in piano ed in salita, di soggetti, maschi e femmine, fisicamente attivi e gli effetti dell’allenamento sul costo energetico del cammino in piano ed in salita;
VII. la pagayata di kayakers e canoisti (canoa canadese) appartenenti alla nazionale juniores di canoa kayak .
Risultati principali:
1. il costo energetico della corsa a navetta intermittente può essere interpolata in modo univoco da una funzione che tenga conto dell’energia cinetica, che nella corsa continua, ovviamente , è nulla, mentre nella corsa intermittente a navetta varia in funzione della distanza e velocità (R2 0,970);
2. dopo 5 settimane di allenamento di corsa a navetta intermittente è migliorato il costo energetico sia della corsa a navetta su 18,5m e su 8,5m (6,10% P< 0,002 e 14,15% P<0,05), che della corsa in linea sul nastro trasportatore (7,06% P< 0,003);
3. nei calciatori dopo un periodo di allenamento di 2 o 6 mesi il costo energetico della corsa in linea, a 13,5 km/h sul nastro, peggiora in maniera significativa in tutti in tutte le squadre valutate (serie A, primavera, C1)(6,23% P< 0,01e 13,81% P< 0,0001);
4. il V’O2max misurato nello yo-yo endurance non è correlato con la distanza percorsa e con quello stimato (R2 0,264 e R2 0,263), e la percentuale di miglioramento del V’O2max misurato non è correlata con quella della distanza percorsa (R2 0,010);
5. il costo energetico della corsa a navetta è maggiore nei maratoneti rispetto ai calciatori presumibilmente perché il gesto non è specifico della disciplina praticata e quindi più dispendioso (8,8% P< 0,01).
6. il costo energetico del cammino in piano ed in salita è maggiore nei maschi rispetto alle femmine (in piano 4, 5, 6 km/h 0% + 16, 9.6 e 7.4% in salita a 5 km/h a pendenza del 5, 10, 15% + 14.3, 16.2, 13.9%) .
7. in kayakers e canoisti (canoa canadese) di alto livello abbiamo correlato la prestazione migliore realizzata in gara con quella calcolata teoricamente. Quest’ultima è stata ottenuta dalla relazione individuale tra Ėr = f (t) ed Ėmax = f (t), dove Ėr è la potenza metabolica richiesta per coprire la distanza in questione ed Ėmax è la massima potenza metabolica. Il tempo t per cui Ėr = Ėmax è stato assunto come il tempo teorico migliore sulla distanza considerata. Tempi e velocità teoriche individuali sono stati essenzialmente uguali a quelle misurate nelle recenti competizioni (R2 0,917).The main purpose of this thesis was to study the energy cost of various forms of human locomotion, in several experimental conditions specifically forms of locomotion, and experimental conditions, were:
I. continuous and intermittent linear and shuttle running;
II. intermittent shuttle running with normal or fast changes of direction, and the effects of 5 weeks of training, on the energy cost of the linear or shuttle intermittent running;
III. linear and shuttle intermittent running of professional soccer players before and after a training period;
IV. yo-yo endurance test and the energy cost of running on line of professional soccer players (Category: Serie A, Primavera, C1) before and after six months of training competition;
V. linear and shuttle running: the difference between professional soccer players and amateur marathoners of good level;
VI. walking on flat terrain and uphill of male and female physically active subjects, and the effects of training on the energy cost of horizontal surface or uphill walking;
VII. Paddling of the kayakers and canoeists (Canadian canoe) belonging to National Junior Canoeing Kayak.
Main results:
1. the energy cost of intermittent shuttle running can be univocally interpolated uniquely by a function taking into account the kinetic energy that, in the continue run, of course, is zero, but in the intermittent shuttle run varies depending on distance and speed (R2 0,970);
2. after 5 weeks of intermittent shuttle running training, the corresponding energy cost over 18.5 m or 8.5 m increased by 6,10% P< 0,002 and 14,15% P<0,05, and that of linear running on the treadmill by 7,06% P< 0,003;
3. in soccer players, after a training period of 2 or 6 months, the energy cost of linear running at 13.5 km/h on the treadmill increased (i.e. became worse) significantly in all teams (Series A , spring, C1 ; by 6,23% (P< 0,01) and 13,81% ( P< 0,0001);
4. V'O2maxmeasured in the yo-yo endurance test is not correlated with the distance covered nor with estimated V'O2max value (R2 0,264 e R2 0,263); nor is the percentage improvement V’O2max correlated with the corresponding distance increase (R2 0,010);
5. the energy cost of shuttle running is higher in marathoners than in to soccer players probably because in the former case shuttle running is not specific to the practiced discipline and therefore more expensive (8,8% P< 0,01);
6. the energy cost of walking on the level or uphill treadmill is greater in males than in females (on flat terrain at 4, 5, 6 km/h by 16, 9.6and 7.4%; at 5 km/h on a 5, 10, 15 %incline by 14.3, 16.2 and 13.9 % respectively);
7. in high level kayakers and canoeists individual best performances achieved in practice were correlated with those theoretically calculated. In turn, these were obtained from the individual relationships Ėr=f(t) and Ėmax=f(t), where Ėr is the metabolic power required to cover the distance in question and Ėmax the maximal metabolic power. The time yielding Ėr=Ėmax was assumed to yield the best performance time. Individual theoretical best times and speeds were essentially equal to those measured during actual competitions(R2 0,917)
Gestione degli animali e alimentazione nella Cisalpina romana: tra archeologia e archeozoologia
No full textBeach volley: estensione della pallavolo indoor o un altro sport? Tempi gioco, altezza di salto ed impegno metabolico nel beach-volley.
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
Modulation of synaptic plasticity by short-term aerobic exercise in adult mice
No full textPhysiological effects of different types, of continuous and interval aerobic training, have been largely described and studied in the adult man. It was previously indicated that interval training plays an important role in maximizing both peripheral muscle and central cardiorespiratory adaptations, permitting significant functional improvement even in healthy sedentary subjects. Since the outcome of different aerobic training trials on cognitive processes had never been evaluated, we compared, on an experimental mouse model, the effects of four training exercise protocols, named respectively C100, I100, C50 and I50 depending on the volume and on the type of training proposed, continuous or interval method. Therefore, to asses quantitative and qualitative functional changes, we analyzed several physical parameters before and after 6 weeks training in all four groups with respect to the control sedentary animals and we studied synaptic plasticity, by extracellular in vitro recordings, in hippocampal mouse slices, a region involved in learning and memory processes. We found that all four protocols of exercise applied in this study exerted positive effects on both physical and training parameters inducing weight augmentation, strength endurance and aerobic endurance increase, and potentiation of motor coordination. However, the improvement observed failed to induce an enhancement in synaptic plasticity in three out of four exercise protocols and only in the slices from mice trained with the interval 50% volume exercise the long term potentiation (LTP) increased with respect to the sedentary group. These findings suggest that motor activity exerts positive effects on cognitive processes provided that certain principles are respected, such as the training load and the elements of which it is composed, in order to plan the right quantitative and qualitative parameters and the appropriate recovery periods
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
DAL TAVOLIERE ALLE MURGE. STORIE DI LANA, DI GRANO E DI SALE IN PUGLIA TRA ETA' ROMANA E MEDIOEVO
No full text- …
