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In this study, we analysed running world records and found that the mean speed of the race, μ, as a function of the record time, τ, can be described asymptotically by two well-defined scaling laws of the form u ?s τ - β. There is a break in the scaling laws (?1000m) between the shorter and the longer races at a characteristic time of around 150-170 s, after which a new scaling regime emerges. This is the first occasion that this characteristic time has been clearly found in physical terms; we interpreted it as the transition time between the anaerobic and the aerobic energy expenditure of athletes. This phenomenon is independent of the athletes' sex and is also found in swimming races with similar values of the characteristic time. We also investigated the forecasting of world records using historical data. Using an approach based on the identification of non-Poissonian events for a sequence of temporal point processes, we found that the sequence of improvements in all athletic records from 1900 to the present day cannot be considered as a sequence of completely random events. 相似文献
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Universities need to maintain data about various resources. They include intellectual creations that are the focus of (Digital) Libraries, but also courses, research projects, and people. Data about intellectual creations are maintained in institutional repositories, while data about courses, research projects, and people reside in various databases designed to support specific vertical applications. We propose a uniform treatment of such resources leading to Digital Universities, i.e., a set of key resources, methodologies, and tools appropriately organized to effectively support universities' users. This requires new methodologies, data models, authority control mechanisms, and system infrastructures that are able to support a broader range of services. 相似文献
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António Natal Campos Rebelo Pedro Silva Vincenzo Rago Daniel Barreira Peter Krustrup 《Journal of sports sciences》2016,34(24):2246-2254
ABSTRACTThe aims of this study were (i) to characterise the acceleration demands of two different formats of small-sided game (SSG), i.e., 4v4 + goalkeepers (4v4 + GK) and 8v8 + goalkeepers (8v8 + GK); (ii) to analyse the correlation between performance in power-based tests and acceleration-based physical loading during the two different SSG formats and (iii) to analyse the neuromuscular-induced fatigue. Eighteen adult male footballers participated in the study (20.7 ± 1.0 years, 178 ± 5 cm and 71.4 ± 2.1 kg). Baseline measurements were obtained from countermovement jumps, 15 s repeated jumps and 5 and 15 m sprints. A total of 36 min was analysed for each SSG (4v4 + GK: two sets of 3 × 6 min, and 8v8 + GK: 2 × 18 min). Heart rate, blood lactate, perceived exertion and movement pattern (GPS) were analysed. Distances covered by very-high-intensity activities and very-high-speed running were lower in 4v4 + GK than in 8v8 + GK (effect sizes (ES) = ?0.69 ± 0.67 and ?1.04 ± 0.67, respectively; very likely), while accelerations and decelerations were higher in 4v4 + GK than in 8v8 + GK (ES = 1.13–1.52; almost certainly). Blood lactate concentrations were higher (ES = 1.40 ± 0.58; almost certainly) and players perceived themselves to be more tired (ES = 0.80–2.31; almost certainly) after 4v4 + GK than after 8v8 + GK. Sprint ability in 5 and 15 m tests decreased (ES = 0.87 ± 0.58 and 0.89 ± 0.58, respectively; almost certainly) only after 4v4 + GK. This SSG format appeared more demanding in relation to repetitions and fatigue development of muscle power-based actions than 8v8 + GK. It may therefore be logical to use the former type of SSG to target development of power-related football actions. 相似文献
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Nelio Marco Vincenzo Bizzo 《科学教学研究杂志》1994,31(5):537-556
Evolution is considered an essential topic that brings to school a broader perspective of natural phenomena and of the nature of science. Most if not all research has shown that the result of the teaching of evolutionary theories is not positive in different parts of the world. Some have attributed the poor understanding shown by students to teaching style or to students' cognitive abilities. This article reports results of interviews and tests carried out with students after they had been taught the topic of evolution. By adopting a sociocultural perspective, before terming students' views “misconceptions,” attention was given to several different ways Charles Darwin's theories have been re-interpreted by well-known scholars and offered to the public. I have analyzed the approaches taken by Emanuel Radl (1873-1942), John C. Greene, Robert Maxwell Young, and Ernst Mayr to assess the diverse ways Darwinism has been conceived. Attention was also given to the presentation of this controversial knowledge to the public in two major popular books written by respected scientists, Huxley and Kettlewell's Darwin and His World (1975) and Richard Dawkins' more recent The Blind Watchmaker (1989). These analyses revealed remarkable differences between what was written in Downe (Kent) a hundred years ago and what was heard at Sao Paulo (Brazil) nowadays. Students show very poor understanding of evolutionary theories. Their conceptions reveal evolution has been primarily related to the human species. Its meaning is understood as similar to progress, growth, multiplication, and improvement. Biological and cultural evolution are not clearly distinguished. Competition is misunderstood as pure violence, sometimes inevitable, and adaptation is considered an individual process that occurs during the organism's life span. Educational change may not depend just on teaching style and students' cognitive abilities. Modification of factual knowledge and epistemological gaps may be the result of a process of social reconceptualization of knowledge offered to students. 相似文献
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Training is an essential part of the professional development of staff working for international humanitarian organizations. While humanitarian workers are being deployed around the world to provide life‐saving relief assistance in often‐hazardous missions, it is imperative for organizations to ensure that staff members understand the mission and protocol of their organizations and that they develop an appreciation for the impact their work has on beneficiaries. Demand for such training has been expanding exponentially over the last decade with the growing number of humanitarian organizations and personnel. In the United Nations alone, an estimated 37,000 civilian personnel are being employed as part of UN humanitarian operations, an increase of 54% since 1997; 75% of this personnel is composed of national staff of the countries of operation (United Nations, 2008). With the increasing reliance of humanitarian organizations on national staff to manage their field operations, the professional development of staff members poses an ever‐growing challenge due to the remoteness and distribution of staff, limiting organizations’ ability to maintain the coherence and cogency of their mission and methods. Although many international humanitarian organizations have adopted some form of distance learning into their staff training, few organizations have evaluated the effectiveness of their distance learning programs. This research briefly evaluates the literature relevant to the use of distance learning for training professional staff in the humanitarian field, assesses how distance learning programs are being used among select humanitarian organizations based in the USA, and reviews the results of a pilot distance learning course offered to mid‐career professionals working on international humanitarian issues in a professional capacity. 相似文献
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Vincenzo Maltese 《Cataloging & classification quarterly》2013,51(7):592-606
AbstractUniversities struggle to offer complete, up-to-date and consistent information about their key assets to their numerous users across various digital services and communication channels. Key assets include people, papers, books, dissertations, patents, courses, and research projects. The main difficulty stands in the intrinsic data fragmentation and data diversity: data about the key assets is scattered across multiple information silos, data is often duplicated and difficult to correlate due to the diversity in the format, metadata, conventions, and terminology used. We illustrate how this difficulty can be tackled and describe the work carried out at the University of Trento in Italy. 相似文献
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Laura Chimenti Giuseppe Morici Alessandra Paternò Anna Bonanno Marcello Vultaggio Vincenzo Bellia 《Journal of sports sciences》2013,31(9):925-935
Abstract Runners have increased numbers of neutrophils in the airways at rest and after exercise compared with sedentary individuals. The aim of this study was to determine whether Mediterranean seasonal changes in temperature, humidity or airborne pollutants affect the airway cells of runners training outdoors in an urban environment. In nine male amateur runners, cell composition, apoptosis, and inflammatory mediators were measured in induced sputum collected at rest (baseline) and the morning after races held in the fall (21 km), winter (12 km), and summer (10 km). Concentrations of air pollutants were below the alert threshold at all times. Neutrophil differential counts tended to increase after all races (P = 0.055). Apoptosis of neutrophils increased with ozone (P < 0.005) and particulate matter <10 μm (PM10) (P < 0.05) exposure. Bronchial epithelial cell counts were low at all times and weakly correlated with ozone and PM10 concentrations. Apoptotic bronchial epithelial cells increased after all races (P < 0.05). Inflammatory mediators in induced sputum were low at baseline and after the races, and correlated with neutrophil differential counts only at rest. In conclusion, apoptosis of airway cells in runners appears to be affected by both exercise and environmental conditions. Apoptosis of neutrophils increased with exposure to environmental pollutants while apoptosis of bronchial epithelial cells increased after intense exercise. Since no relationship was observed between neutrophil counts and inflammatory mediators 20 h after races, airways inflammation at this time point appears blunted in healthy runners and little affected by exposure to mild seasonal changes and airborne pollutants. 相似文献