The dynamic of bicycle finals: A theoretical and empirical analysis of slipstreaming

The finals of bicycle races have certain peculiarities compared to other sports. The leading group in a bicycle race rides comparatively slowly up to a few meters before the finishing line, until one of the competitors tries to shake off his opponents. Only then do all riders perform to the limit. This raises the question of who takes the thankless early lead and why. The rider who is in front just before the final sprint is seldom the one who wins in the end. By means of the relevant physics it can be shown theoretically that on the one hand the better rider will always be able to win the race and, more surprisingly on the other hand, the better rider will definitely be the rider in the slipstream. These findings are confirmed empirically by means of several logistic regressions. 49 final sprints of road races between two up to seven professional racing cyclists with varying performance potentials were analyzed concerning the order of the riders at the beginning of the final sprint and the final outcome of the race. Subsequently, possibilities for further research and implications for sport economics are described. -- Sprintentscheidungen im Radsport weisen im Vergleich zu anderen Sportarten einige Besonderheiten auf. Die in einem Radrennen führende Gruppe fährt bis wenige Meter vor die Ziellinie vergleichsweise langsam, bevor dann ein Fahrer kurz vor dem Ziel versucht, seine Konkurrenten abzuschütteln. Erst dann erreichen die Fahrer ihre Höchstgeschwindigkeit. Der zu Beginn des Sprints in Führung liegende Rennfahrer gewinnt dabei in den seltensten Fällen am Ende auch das Rennen. Daher stellt sich die Frage, wer zu Beginn des Sprints die undankbarer Führungsposition im Wind übernimmt und warum. Zunächst kann mittels grundlegender Physik theoretisch gezeigt werden, dass zum einen der bessere Fahrer immer in der Lage sein wird, das Rennen zu gewinnen, und zum anderen, weniger naheliegend, der bessere Fahrer stets zu Beginn des Sprints im Windschatten fahren wird. Diese theoretischen Ergebnisse werden anschließend empirisch anhand logistischer Regressionen bestätigt. 49 Sprintentscheidungen in Straßenradrennen zwischen zwei bis sieben professionellen Radrennfahrern mit unterschiedlichen Leistungsstärken werden auf die Reihenfolge der Fahrer zu Beginn des Sprints und das Ergebnis des Rennens hin untersucht. Abschließend werden Möglichkeiten für weitere Untersuchungen sowie sportökonomische Implikationen dargestellt.

Are three points for a win really better than two? Theoretical and empirical evidence for German soccer

The effects of the three-point rule in first league German soccer are tested empirically and compared to games from the German cup-competition. The inclusion of cup games ensures that changes in league games can be attributed to the three-point rule. As a result of their relative devaluation, the number of draws should decrease. Furthermore, an increase in the number of close wins is expected. The strategy of a leading team becomes more defensive, resulting in fewer goal shootings by that team, as well as fewer shooting opportunities for the opponent. Empirical evidence supporting these effects is found. --

Asymmetric Information in Automobile Insurance: Evidence from Driving Behavior

Based on a unique data set of driving behavior we test whether private information in driving characteristics has significant effects on contract choice and risk in automobile insurance. We define a driving factor based on overall distance driven, number of car rides, and speeding. Using local weather conditions, we account for the endogeneity of the driving factor. While this driving factor has an effect on risk, there is no significant evidence for selection effects in the level of third-party liability and first-party insurance coverage

Corporate governance and employee power in the boardroom: An applied game theoretical analysis

The discussion about employee representation on supervisory boards has received much attention from scholars and politicians around the world. We provide new insights to this ongoing debate by employing power indices from game theory to examine the real power of employees on boards and its effect on firm performance. Based on unique panel data of the largest listed companies in Germany, we find an inversely U-shaped relationship between labour power and Tobin's Q with a value-maximising labour power of approximately 43 %. Our results are robust to different game theoretical calculations of labour power, as well as various econometric models.Die Diskussion über Arbeitnehmermitbestimmung in Aufsichtsräten hat erhebliche Aufmerksamkeit von Wissenschaftlern und Politiker in vielen Ländern erfahren. Wir tragen neue Einsichten zu dieser fortdauernden Debatte bei, indem wir spieltheoretische Machtindices verwenden, um die Macht von Beschäftigten und deren Beitrag zum Unternehmenserfolg zu bestimmen. Mit originären Paneldaten der größten deutschen gelisteten Unternehmen finden wir eine umgekehrt U-förmige Beziehung zwischen Arbeitnehmermacht und Tobin's Q, wobei die wertmaximierende Arbeitnehmermacht bei rund 43 % liegt. Unsere Ergebnisse sind robust sowohl hinsichtlich unterschiedlicher spieltheoretischer Berechnungen der Arbeitnehmermacht als auch verschiedener ökonometrischer Modellierungen.

Ultrametric probe of the spin-glass state in a field

We study the ultrametric structure of phase space of one-dimensional Ising spin glasses with random power-law interaction in an external random field. Although in zero field the model in both the mean-field and non-mean-field universality classes shows an ultrametric signature [Phys. Rev. Lett. 102, 037207 (2009)], when a field is applied ultrametricity seems only present in the mean-field regime. The results for the non-mean field case in an external field agree with data for spin glasses studied within the Migdal-Kadanoff approximation. Our results therefore suggest that the spin-glass state might be fragile to external fields below the upper critical dimension.Comment: 5 pages, 4 figures, 1 tabl

Optimal Vertex Cover for the Small-World Hanoi Networks

The vertex-cover problem on the Hanoi networks HN3 and HN5 is analyzed with an exact renormalization group and parallel-tempering Monte Carlo simulations. The grand canonical partition function of the equivalent hard-core repulsive lattice-gas problem is recast first as an Ising-like canonical partition function, which allows for a closed set of renormalization group equations. The flow of these equations is analyzed for the limit of infinite chemical potential, at which the vertex-cover problem is attained. The relevant fixed point and its neighborhood are analyzed, and non-trivial results are obtained both, for the coverage as well as for the ground state entropy density, which indicates the complex structure of the solution space. Using special hierarchy-dependent operators in the renormalization group and Monte-Carlo simulations, structural details of optimal configurations are revealed. These studies indicate that the optimal coverages (or packings) are not related by a simple symmetry. Using a clustering analysis of the solutions obtained in the Monte Carlo simulations, a complex solution space structure is revealed for each system size. Nevertheless, in the thermodynamic limit, the solution landscape is dominated by one huge set of very similar solutions.Comment: RevTex, 24 pages; many corrections in text and figures; final version; for related information, see http://www.physics.emory.edu/faculty/boettcher

A simple location-tracking app for psychological research

Location data gathered from a variety of sources is particularly valuable when it comes to understanding individuals and groups. However, much of this work relies on participants’ active engagement to regularly report their location. More recently, smartphones have been used to assist with this process, but while commercial smartphone applications are available, these are often expensive and not designed with researchers in mind. In order to overcome these and other related issues, we have developed a freely available Android application that logs location accurately, stores data securely, and ensures participants can provide consent or withdraw from a study at any time. Further recommendations and R code are provided to assist with subsequent data analysis

Global Gene Expression Analysis in the Livers of Rat Offspring Perinatally Exposed to Low Doses of 2,2′,4,4′-Tetrabromodiphenyl Ether

BACKGROUND: Polybrominated diphenyl ethers are a group of flame-retardant chemicals appearing increasingly in the environment. Their health effects and mechanisms of toxicity are poorly understood. OBJECTIVES: We screened for the sensitive effects and mechanisms of toxicity of 2,2 ,4,4 -tetra-bromodiphenyl ether (BDE-47) by analyzing the gene expression profile in rats exposed to doses comparable to human exposure. METHODS: Wistar dams were exposed to vehicle or BDE-47 (0.002 and 0.2 mg/kg body weight) every fifth day from gestation day 15 to postnatal day 20 by injections to caudal vein. Total RNA was extracted from the livers of pups and hybridized to the whole-genome RNA expression micro-arrays. The list of genes 2-fold differentially expressed was exported to PANTHER and Ingenuity Systems for analysis of enriched ontology groups and molecular pathways. RESULTS: Oxidoreductase and transferase protein families were enriched in exposed rats as were these biological process categories: carbohydrate metabolism; electron transport; and lipid, fatty acid, and steroid metabolism. Four signaling pathways (cascades of activation of drug-metabolizing enzymes) and 10 metabolic pathways were significantly enriched. Drug-metabolizing enzymes appear to be regulated by BDE-47 through an aryl hydrocarbon receptor-independent mechanism. Direct interaction with retinoid X receptor or its upstream cascade may be involved. The main metabolic effects consisted of activation of metabolic pathways: alpha- and omega-oxidation of fatty acids, glycolysis, and starch hydrolysis. CONCLUSIONS: Altered expression of genes involved in metabolic and signaling pathways and functions of the organism occurs after perinatal exposure of rat offspring to BDE-47 at doses relevant for the general population

Überzeugungen und Einstellungen von Lehrkräften: Definition und Vermittlung der Bedeutung von Formeln

Wir berichten über eine Untersuchung in der 244 Physiklehrerinnen und -lehrer schriftlich zu ihren Einstellungen und Überzeugungen gegenüber Formeln in der Physik und im Physikunterricht befragt wurden. In diesem Artikel liegt der Schwerpunkt darauf, wie Lehrerinnen und Lehrer den Begriff Formel für sich definieren und welche Möglichkeiten Lehrerinnen und Lehrer sehen, Schülerinnen und Schülern die Bedeutung von Formeln näherzubringen.Im Rahmen einer qualitativen Inhaltsanalyse der gegebenen Antworten wurde für beide Fragestellungen jeweils ein Kategoriensystem induktiv erstellt. Mithilfe eines Codierschemas wurde die Zuordnungshäufigkeit der Aussagen der Probanden zu den entwickelten Haupt- und Unterkategorien quantitativ analysiert.Definieren Lehrerinnen und Lehrer den Formelbegriff für sich selbst, stehen deskriptive und nominative Aspekte der Formelnutzung im Vordergrund. Bei der Vermittlung der Bedeutung von Formeln treten präskriptive Aspekte an deren Stelle. Die Nutzung von Formeln, um Vorhersagen zu treffen, soll implizit durch häufiges Anwenden und Einüben beim Problemlösen erlernt werden