The distance-time relationship over a century of running Olympic performances: A limit on the critical speed concept     

Dekerle J  Nesi X  Carter H 《Journal of sports sciences》2006,24(11):1213-1221

We analyse the evolution of the slope (critical speed) and the y-intercept (anaerobic distance capacity) of the linear distance-time relationship over a century of Olympic running performances. The distance-time relationship of each Olympic Games (1920-2004) was plotted using the performances in the 800-, 1500- and 5000-m track events. Values for critical speed and anaerobic distance capacity were determined by linear modelling. Mean performances for the 800, 1500 and 5000 m were 104.9 +/- 1.5 s (1.4%), 217.2 +/- 2.8 s (1.3%) and 808.9 +/- 18.4 s (2.3%), respectively. Critical speed improved during the first three-quarters of the twentieth century to reach a plateau in 1984. This is in accordance with the literature (Peronnet & Thibault, 1989) and suggests that "human aerobic endurance" has improved within the century (+13.4%) and tends to stabilize. Anaerobic distance capacity was highly variable over the century (coefficient of variation = 9.4%) and did not show a linear improvement over the years as has previously been suggested (Peronnet & Thibault, 1989). This could be due to an artefact in the application of the two-parameter model to only three Olympic performances. A limitation to the use of this linear mathematical model to fit physiological data may have been demonstrated.  相似文献   

Centralizing motive power     

J. Richards 《Journal of The Franklin Institute》1870,90(3):185-187

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Glimpses of the international electrical exhibition     

Edwin J. Houston 《Journal of The Franklin Institute》1885,119(5):410-423

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Accurate assessment of the brake torque on a rope-braked cycle ergometer     

Gordon  R. S.  Franklin  K. L.  Baker  J.  Davies  B. 《Sports Engineering》2004,7(3):131-138

Sports Engineering - A Monark cycle ergometer is a device globally used in physiological studies to measure the work and energy levels of exercising humans. In this paper a rope-braked cycle...  相似文献   

The impact of case characteristics on child abuse reporting decisions.     

G L Zellman 《Child abuse & neglect》1992,16(1):57-74

Drawing distinctions on the basis of at least some case characteristics in making reporting decisions makes considerable sense. Using data from a national survey of mandated reporters that included vignettes in which case and personal characteristics were systematically varied, this paper examines the impact of selected characteristics while controlling for others. The data reveal that respondents noticed and responded to case characteristics. Abuse-relevant judgments and reporting intentions varied, often substantially, as a function of case characteristics. Three case characteristics--previous abuse, severity of abuse, and recantation--were powerful predictors of vignette outcomes. A history of previous abuse led to judgments of greater seriousness, a more salutary impact of a report, and greater likelihood of reporting. More severe abuse was more likely to be labelled as abuse, and was more likely to be reported. When the alleged victim retracted her accusation upon questioning by an authority figure, respondents were significantly less likely to intend a report. Child age, perpetrator intent and family socioeconomic status also influenced abuse-relevant judgments and reporting intentions. Respondents were more likely to intend a report when younger children, lazy or angry perpetrators and children from poorer families were portrayed.  相似文献   

Probabilistic Causality,     

L. JONATHAN COHEN 《Philosophical Books》1992,33(2):86-88

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REAL: Ein ressourcenadaptierendes mobiles Navigationssystem     

Wolfgang Wahlster  J?rg Baus  Christian Kray und Antonio Krüger 《Informatik - Forschung und Entwicklung》2001,16(4):233-241

Zusammenfassung.   Die intelligente Ressourcenadaption ist eine der gro?en Herausforderungen für die n?chste Generation mobiler Navigationssysteme. Da man typischerweise mehrere Fortbewegungsarten oder Verkehrsmittel kombinieren muss, um an einen Zielort zu gelangen, muss sichergestellt werden, dass mobile, allgegenw?rtige Navigationshilfen dies über eine jeweils situationsangepasste Benutzerschnittstelle unterstützen. Der notwendige Wechsel zwischen verschiedenen Positionierungstechnologien soll für den Endbenutzer m?glichst unbemerkt bleiben. Im folgenden wird ein hybrides Personennavigationssystem vorgestellt, das die in bestimmten Fortbewegungssituationen verfügbaren Positionierungstechnologien und deren Genauigkeit optimal nutzt, um die Pr?sentation der Wegbeschreibung auf verschiedene Endger?te und Ausgabemodalit?ten sowie die kognitive Ressourcenlage des Benutzers zu adaptieren. Eingegangen am 28. Februar 2001 / Angenommen am 8. August 2001  相似文献   

Organic reaction mechanisms     

J. Chandrasekhar  Uday Maitra 《Resonance》1997,2(7):87-88

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Book reviews     

Ronald J. Zboray  Anita A. Jones  Shirley Kessel  Clarkson N. Potter  Megan Benton  William A. Wortman  Barbara Kiefer  Richard C. Rowson 《Publishing Research Quarterly》1992,8(4):86-106

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Assessing the Utility of Item Response Models: Computerized Adaptive Testing     

G. Gage Kingsbury  Ronald L. Houser 《Educational Measurement》1993,12(1):21-27

How has Item Response Theory helped solve problems in the development and use of computer-adaptive tests? Do we need to balance item content with computer-adaptive tests? Could we use IRT to evaluate unusual responses to computer-delivered tests?  相似文献