Performing under pressure: Exploring the psychological state underlying clutch performance in sport

Clutch performance is improved performance under pressure. However, little research has examined the psychological state experienced by athletes in these situations. Therefore, this study qualitatively examined the subjective experience underlying clutch performance across a range of sports (e.g., team, individual) and standards (Olympic to recreational athletes). Sixteen athletes (M_age = 27.08 years; SD = 6.48) took part in in-depth, semi-structured interviews primarily after an exceptional performance (M = 4.38 days later; SD = 3.14). Data were analysed inductively and thematically. Clutch states involved 12 characteristics, including heightened and deliberate concentration, intense effort, and heightened awareness, which distinguished the experience of clutch from other optimal psychological states such as flow. Other characteristics, such as perceptions of control, were also reported and supported previous experimental research on clutch. These findings present in-depth qualitative insights into the psychological state underlying clutch performance, and are discussed in relation to the existing literature on optimal psychological states in sport.     

Motion Pictures

Richard Bunce's Television in the Corporate Interest (New York: Praeger Special Studies, 1976—price not given, but about $15.00).

Ralph M. Jennings and Veronica M. Jefferson's Television Station Employment Practices, 1975: The Status of Minorities and Women (New York: Office of Communication, United Church of Christ, 1976—price not given, but about $10.00, paper)

Horace Newcomb's Television: The Critical View (New York: Oxford University Press, 1976—$4.00, paper)

Asa Berger's The TV-Guided American (New York: Walker, 1976—$8.95)

Vincent Mosco's The Regulation of Innovations in the Broadcasting Market (Cambridge, Mass.: Harvard University Program on Information Technologies and Public Policy, 1975—$3.00, paper)

James D. Scott's Cable Television: Strategy for Penetrating Key Urban Markets (Ann Arbor: University of Michigan Graduate School of Business Administration, 1976—$5.50, paper)

R.W. Chandler's Sparks at Sea: The Experiences of a Ship's Radio Officer (North Pomfret, Vt.: David and Charles, 1973, but only recently released in the U.S.—$9.50)     

Das MINERVA-Projekt: Datenbankselektion für Peer-to-Peer-Websuche

Zusammenfassung In diesem Artikel wird MINERVA pr?sentiert, eine prototypische Implementierung einer verteilten Suchmaschine basierend auf einer Peer-to-Peer (P2P)-Architektur. MINERVA setzt auf die in der P2P-Welt verbreitete Technik verteilter Hash-Tabellen auf und benutzt diese zum Aufbau eines verteilten Verzeichnisses. Peers in unserem Ansatz entsprechen v?llig autonomen Benutzern mit ihren lokalen Suchm"oglichkeiten, die bereit sind, ihr lokales Wissen und ihre lokalen Suchm?glichkeiten im Rahmen einer Kollaboration zur Verfügung zu stellen. Wir formalisieren unsere Systemarchitektur und beschreiben das zentrale Problem einer effizienten Suche nach vielversprechenden Peers für eine konkrete Anfrage innerhalb des Verbundes. Wir greifen dabei auf existierende Methoden zurück and passen diese an unseren Systemkontext an. Wir pr?sentieren Experimente auf realen Daten, die verschiedene dieser Ans?tze vergleichen. Diese Experimente zeigen, dass die Qualit?t der Ans?tze variiert und untermauern damit die Wichtigkeit und den Einfluss einer leistungsstarken Methode zur Auswahl guter Datenbanken. Unsere Experimente deuten an, dass eine geringe Anzahl sorgf?ltig ausgew?hlter Datenbanken typischerweise bereits einen Gro?teil aller relevanten Ergebnisse des Gesamtsystems liefert.

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This paper presents the MINERVA project that protoypes a distributed search engine based on P2P techniques. MINERVA is layered on top of a Chord-style overlay network and uses a powerful crawling, indexing, and search engine on every autonomous peer. We formalize our system model and identify the problem of efficiently selecting promising peers for a query as a pivotal issue. We revisit existing approaches to the database selection problem and adapt them to our system environment. Measurements are performed to compare different selection strategies using real-world data. The experiments show significant performance differences between the strategies and prove the importance of a judicious peer selection strategy. The experiments also present first evidence that a small number of carefully selected peers already provide the vast majority of all relevant results.

CR Subject Classification H.4,H.3.3,H3.4     

Predictive value of ventilatory inflection points determined under field conditions

The aim of this study was to evaluate the predictive potential provided by two ventilatory inflection points (VIP₁ and VIP₂) examined in field without using gas analysis systems and uncomfortable facemasks. A calibrated respiratory inductance plethysmograph (RIP) and a computerised routine were utilised, respectively, to derive ventilation and to detect VIP₁ and VIP₂ during a standardised field ramp test on a 400 m running track on 81 participants. In addition, average running speed of a competitive 1000 m run (S_1k) was observed as criterion. The predictive value of running speed at VIP₁ (S_VIP1) and the speed range between VIP₁ and VIP₂ in relation to VIP₂ (VIP_SPAN) was analysed via regression analysis. VIP_SPAN rather than running speed at VIP₂ (S_VIP2) was operationalised as a predictor to consider the covariance between S_VIP1 and S_VIP2. S_VIP1 and VIP_SPAN, respectively, provided 58.9% and 22.9% of explained variance in regard to S_1k. Considering covariance, the timing of two ventilatory inflection points provides predictive value in regard to a competitive 1000 m run. This is the first study to apply computerised detection of ventilatory inflection points in a field setting independent on measurements of the respiratory gas exchange and without using any facemasks.     

The impact of participation in sports on educational attainment—New evidence from Germany

We analyze the impact of exercising sports during childhood and adolescence on educational attainment. The theoretical framework is based on models of allocation of time and educational productivity. Using the rich information from the German Socio-Economic Panel (GSOEP), we apply generalized ordered probit models to estimate the effect of participation in sport activities on secondary school degrees and professional degrees. Even after controlling for important variables and selection into sport, we find strong evidence that the effect of sport on educational attainment is statistically significant and positive.     

Efficient reverse k-nearest neighbor estimation

The reverse k-nearest neighbor (RkNN) problem, i.e. finding all objects in a data set the k-nearest neighbors of which include a specified query object, has received increasing attention recently. Many industrial and scientific applications call for solutions of the RkNN problem in arbitrary metric spaces where the data objects are not Euclidean and only a metric distance function is given for specifying object similarity. Usually, these applications need a solution for the generalized problem where the value of k is not known in advance and may change from query to query. In addition, many applications require a fast approximate answer of RkNN-queries. For these scenarios, it is important to generate a fast answer with high recall. In this paper, we propose the first approach for efficient approximative RkNN search in arbitrary metric spaces where the value of k is specified at query time. Our approach uses the advantages of existing metric index structures but proposes to use an approximation of the nearest-neighbor-distances in order to prune the search space. We show that our method scales significantly better than existing non-approximative approaches while producing an approximation of the true query result with a high recall.