1000 resultados para Ball games


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Welsch (Projektbearbeiter): Festgedicht anläßlich eines 'demokratischen Balls', das auch angesichts der Niederschlagung der Revolution trotzige Siegesgewißheit für die Zukunft ausdrückt

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Introduction: In team sports the ability to use peripheral vision is essential to track a number of players and the ball. By using eye-tracking devices it was found that players either use fixations and saccades to process information on the pitch or use smooth pursuit eye movements (SPEM) to keep track of single objects (Schütz, Braun, & Gegenfurtner, 2011). However, it is assumed that peripheral vision can be used best when the gaze is stable while it is unknown whether motion changes can be equally well detected when SPEM are used especially because contrast sensitivity is reduced during SPEM (Schütz, Delipetkose, Braun, Kerzel, & Gegenfurtner, 2007). Therefore, peripheral motion change detection will be examined by contrasting a fixation condition with a SPEM condition. Methods: 13 participants (7 male, 6 female) were presented with a visual display consisting of 15 white and 1 red square. Participants were instructed to follow the red square with their eyes and press a button as soon as a white square begins to move. White square movements occurred either when the red square was still (fixation condition) or moving in a circular manner with 6 °/s (pursuit condition). The to-be-detected white square movements varied in eccentricity (4 °, 8 °, 16 °) and speed (1 °/s, 2 °/s, 4 °/s) while movement time of white squares was constant at 500 ms. 180 events should be detected in total. A Vicon-integrated eye-tracking system and a button press (1000 Hz) was used to control for eye-movements and measure detection rates and response times. Response times (ms) and missed detections (%) were measured as dependent variables and analysed with a 2 (manipulation) x 3 (eccentricity) x 3 (speed) ANOVA with repeated measures on all factors. Results: Significant response time effects were found for manipulation, F(1,12) = 224.31, p < .01, ηp2 = .95, eccentricity, F(2,24) = 56.43; p < .01, ηp2 = .83, and the interaction between the two factors, F(2,24) = 64.43; p < .01, ηp2 = .84. Response times increased as a function of eccentricity for SPEM only and were overall higher than in the fixation condition. Results further showed missed events effects for manipulation, F(1,12) = 37.14; p < .01, ηp2 = .76, eccentricity, F(2,24) = 44.90; p < .01, ηp2 = .79, the interaction between the two factors, F(2,24) = 39.52; p < .01, ηp2 = .77 and the three-way interaction manipulation x eccentricity x speed, F(2,24) = 3.01; p = .03, ηp2 = .20. While less than 2% of events were missed on average in the fixation condition as well as at 4° and 8° eccentricity in the SPEM condition, missed events increased for SPEM at 16 ° eccentricity with significantly more missed events in the 4 °/s speed condition (1 °/s: M = 34.69, SD = 20.52; 2 °/s: M = 33.34, SD = 19.40; 4 °/s: M = 39.67, SD = 19.40). Discussion: It could be shown that using SPEM impairs the ability to detect peripheral motion changes at the far periphery and that fixations not only help to detect these motion changes but also to respond faster. Due to high temporal constraints especially in team sports like soccer or basketball, fast reaction are necessary for successful anticipation and decision making. Thus, it is advised to anchor gaze at a specific location if peripheral changes (e.g. movements of other players) that require a motor response have to be detected. In contrast, SPEM should only be used if a single object, like the ball in cricket or baseball, is necessary for a successful motor response. References: Schütz, A. C., Braun, D. I., & Gegenfurtner, K. R. (2011). Eye movements and perception: A selective review. Journal of Vision, 11, 1-30. Schütz, A. C., Delipetkose, E., Braun, D. I., Kerzel, D., & Gegenfurtner, K. R. (2007). Temporal contrast sensitivity during smooth pursuit eye movements. Journal of Vision, 7, 1-15.

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Several theories assume that successful team coordination is partly based on knowledge that helps anticipating individual contributions necessary in a situational task. It has been argued that a more ecological perspective needs to be considered in contexts evolving dynamically and unpredictably. In football, defensive plays are usually coordinated according to strategic concepts spanning all members and large areas of the playfield. On the other hand, fewer people are involved in offensive plays as these are less projectable and strongly constrained by ecological characteristics. The aim of this study is to test the effects of ecological constraints and player knowledge on decision making in offensive game scenarios. It is hypothesized that both knowledge about team members and situational constraints will influence decisional processes. Effects of situational constraints are expected to be of higher magnitude. Two teams playing in the fourth league of the Swiss Football Federation participate in the study. Forty customized game scenarios were developed based on the coaches’ information about player positions and game strategies. Each player was shown in ball possession four times. Participants were asked to take the perspective of the player on the ball and to choose a passing destination and a recipient. Participants then rated domain specific strengths (e.g., technical skills, game intelligence) of each of their teammates. Multilevel models for categorical dependent variables (team members) will be specified. Player knowledge (rated skills) and ecological constraints (operationalized as each players’ proximity and availability for ball reception) are included as predictor variables. Data are currently being collected. Results will yield effects of parameters that are stable across situations as well as of variable parameters that are bound to situational context. These will enable insight into the degree to which ecological constraints and more enduring team knowledge are involved in decisional processes aimed at coordinating interpersonal action.

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Introduction: According to the ecological view, coordination establishes byvirtueof social context. Affordances thought of as situational opportunities to interact are assumed to represent the guiding principles underlying decisions involved in interpersonal coordination. It’s generally agreed that affordances are not an objective part of the (social) environment but that they depend on the constructive perception of involved subjects. Theory and empirical data hold that cognitive operations enabling domain-specific efficacy beliefs are involved in the perception of affordances. The aim of the present study was to test the effects of these cognitive concepts in the subjective construction of local affordances and their influence on decision making in football. Methods: 71 football players (M = 24.3 years, SD = 3.3, 21 % women) from different divisions participated in the study. Participants were presented scenarios of offensive game situations. They were asked to take the perspective of the person on the ball and to indicate where they would pass the ball from within each situation. The participants stated their decisions in two conditions with different game score (1:0 vs. 0:1). The playing fields of all scenarios were then divided into ten zones. For each zone, participants were asked to rate their confidence in being able to pass the ball there (self-efficacy), the likelihood of the group staying in ball possession if the ball were passed into the zone (group-efficacy I), the likelihood of the ball being covered safely by a team member (pass control / group-efficacy II), and whether a pass would establish a better initial position to attack the opponents’ goal (offensive convenience). Answers were reported on visual analog scales ranging from 1 to 10. Data were analyzed specifying general linear models for binomially distributed data (Mplus). Maximum likelihood with non-normality robust standard errors was chosen to estimate parameters. Results: Analyses showed that zone- and domain-specific efficacy beliefs significantly affected passing decisions. Because of collinearity with self-efficacy and group-efficacy I, group-efficacy II was excluded from the models to ease interpretation of the results. Generally, zones with high values in the subjective ratings had a higher probability to be chosen as passing destination (βself-efficacy = 0.133, p < .001, OR = 1.142; βgroup-efficacy I = 0.128, p < .001, OR = 1.137; βoffensive convenience = 0.057, p < .01, OR = 1.059). There were, however, characteristic differences in the two score conditions. While group-efficacy I was the only significant predictor in condition 1 (βgroup-efficacy I = 0.379, p < .001), only self-efficacy and offensive convenience contributed to passing decisions in condition 2 (βself-efficacy = 0.135, p < .01; βoffensive convenience = 0.120, p < .001). Discussion: The results indicate that subjectively distinct attributes projected to playfield zones affect passing decisions. The study proposes a probabilistic alternative to Lewin’s (1951) hodological and deterministic field theory and enables insight into how dimensions of the psychological landscape afford passing behavior. Being part of a team, this psychological landscape is not only constituted by probabilities that refer to the potential and consequences of individual behavior, but also to that of the group system of which individuals are part of. Hence, in regulating action decisions in group settings, informers are extended to aspects referring to the group-level. References: Lewin, K. (1951). In D. Cartwright (Ed.), Field theory in social sciences: Selected theoretical papers by Kurt Lewin. New York: Harper & Brothers.

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The article approaches an understanding of power within strategy formation processes established by verbal and bodily communication. On this note, we examined concepts of power constituted by hierarchy and developed a conceptual framework for a performative interpretation of power. In line with Austin’s (1962) and Butler’s (1990, 1993, 1997) concept of performativity as well as strategy-as-practice research (Balogun et al., 2007; Jarzabkowski & Spee, 2009) we ask: How is persuasion achieved by strategic actors during strategy formation processes? To explore verbal and bodily communication empirically we developed an experimental setting in a small high-tech company located in Germany in December, 2012. The Results indicate that (1) during critical incidents – when perspectives clash – actors use arguments to gain persuasion. (2) The data illustrates that independently of their hierarchical position within the company, strategic actors show an equal distribution of argumentative techniques.

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In recent decades, countless scholars have examined the developing trend of African American dominance in United States’ professional sports. Many have hypothesized that this over-representation is caused by the presumed reliance on sports as an avenue out of poverty for the African American youths. This trend, it is believed, has a highly detrimental effect the African American community. In actuality, this argument is flawed because it works under the stereotypical assumption that the overwhelming majority of African Americans come from abject poverty. To dispel this fallacy, the author has analyzed the upbringings of each All-National Basketball League First Team player over the past thirty years. The author discovered that while the majority of the players selected were African American, only a small percentage of these athletes were raised in a poverty-stricken environment. Logically, this would not be the case if poor African Americans relied more heavily on sports than middle-class African Americans. This data proves that stereotypes, not empirical evidence, are the substance of nearly every previous study conducted on the topic.

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The skinned portions of baseball and softball infields vary widely with respect to soil texture, applied amendments and conditioners, and water management. No studies have been reported that quantify the effects of these varying construction and maintenance practices on the playability of the skinned portions of infields. In Connecticut, USA, skinned infield plots were constructed from five different soils (silt loam, loam, coarse sandy loam, loamy sand, loamy coarse sand) and amended with four rates of calcined clay (0, 4.9, 9.8, 19.6 kg m–2) to determine the effects on surface hardness, traction, and ball-to-surface friction (static and dynamic) at varying soil moisture contents (10, 14, and 18%). Bulk density, saturated hydraulic conductivity, and shear strength of the different soil–calcined clay rate combinations were determined. Increasing the rate of calcined clay decreased bulk density and shear strengths, and increased saturated hydraulic conductivity. Surface hardness increased more with coarse-textured soils and increasing calcined clay rate, but decreased more with fine-textured soils and increasing soil moisture. Increasing the calcined clay rate resulted in decreases in ball-to-surface static friction across all soils and decreased dynamic friction with the fine-textured soils. Increases in soil moisture increased friction in all soils. The fine-textured soils had greater traction than the sandy soils, but no consistent calcined clay or moisture effects on traction were observed. Shear strength of the soils was highly correlated with traction and friction. The results suggest that differences in skinned infield soils are quantifiable, which could lead to the development of playing surface standards.

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Agents on the same side of a two-sided matching market (such as the marriage or labor market) compete with each other by making self-enhancing investments to improve their worth in the eyes of potential partners. Because these expenditures generally occur prior to matching, this activity has come to be known in recent literature (Peters, 2007) as pre-marital investment. This paper builds on that literature by considering the case of sequential pre-marital investment, analyzing a matching game in which one side of the market invests first, followed by the other. Interpreting the first group of agents as workers and the other group as firms, the paper provides a new perspective on the incentive structure that is inherent in labor markets. It also demonstrates that a positive rate of unemployment can exist even in the absence of matching frictions. Policy implications follow, as the prevailing set of equilibria can be altered by restricting entry into the workforce, providing unemployment insurance, or subsidizing pre-marital investment.

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The first professional base ball clubs came in two varieties: stock clubs, which paid their players fixed wages, and player cooperatives, in which players shared the proceeds after expenses. We argue that stock clubs were formed with players of known ability, while co-ops were formed with players of unknown ability. Although residual claimancy served to screen out players of inferior ability in co-ops, the process was imperfect due to the team production problem. Based on this argument, we suggest that co-ops functioned as an early minor league system where untried players could seek to prove themselves and eventually move up to wage teams. Empirical analysis of data on player performance and experience in early professional base ball provides support for the theory.

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Purpose. To determine the usability of two video games to prevent type 2 diabetes and obesity among youth through analysis of data collected during alpha-testing. ^ Subjects. Ten children aged 9 to 12 were selected for three 2-hour alpha testing sessions.^ Methods. "Escape from Diab" and "Nanoswarm" were designed to change dietary and physical inactivity behaviors, based on a theoretical framework of mediating variables obtained from social cognitive theory, self-determination theory, elaboration likelihood model, and behavioral inoculation theory. Thirteen mini-games developed by the software company were divided into 3 groups based on completion date. Children tested 4-5 mini-games in each of three sessions. Observed game play was followed by a scripted interview. Results from observation forms and interview transcripts were tabulated and coded to determine usability. Suggestions for game modifications were delivered to the software design firm, and a follow-up table reports rationale for inclusion or exclusion of such modifications.^ Results. Participants were 50% frequent video game players and 20% non game-players. Most (60%) were female. The mean grade (indicating likeability as a subset of usability) across all games given by children was significantly greater than a neutral grade of 80% (89%, p < 0.01), indicating a positive likeability score. The games on average also received positive ratings for fun, helpfulness of instructions and length compared to neutral values (midpoint on likert scales) (all p < 0.01). Observation notes indicated that participants paid attention to the instructions, did not appear to have much difficulty with the games, and were "not frustrated", "not bored", "very engaged", "not fidgety" and "very calm" (all p < 0.01). The primary issues noted in observations and interviews were unclear instructions and unclear purpose of some games. Player suggestions primarily involved ways to make on screen cues more visible or noticeable, instructions more clear, and games more elaborate or difficult.^ Conclusions. The present study highlights the importance of alpha testing video game components for usability prior to completion to enhance usability and likeability. Results indicate that creating clear instructions, making peripheral screen cues more eye-catching or noticeable, and vigorously stating the purpose of the game to improve understandability are important elements. However, future interventions will each present unique materials and user-interfaces and should therefore also be thoroughly alpha-tested. ^

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Se analiza la lucha fratricida entre Pedro I y Enrique II de Castilla a la luz del "Cuento de los Reyes" inserto en El Victorial, de Gutierre Díaz de Games, y de las Crónicas de Pero López de Ayala. En el transcurso de una guerra civil, inscripta en un conflicto aún mayor, la Guerra de los Cien Años, dos reyes luchan por la misma corona. Ya que Pedro I tiene un origen claramente legítimo, los cronistas, favorables al usurpador Enrique, deben crear para éste una legitimidad, basada en este caso en la denuncia del profundo daño que causa al reino la notoria inconducta del rey legítimo. Una vez perpetrado el doble crimen que significa el asesinato de Pedro a manos de Enrique ?a la vez fratricidio y regicidio? se ejerce la violencia en su función fundacional, instaurando a la vez un nuevo reinado y una nueva dinastía. Por otra parte, lo que sucede en la cúspide de la sociedad se repite en otros niveles, ya que en la guerra civil también se cometerían fratricidios, porque el enemigo no es el Otro, sino un Igual.

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Fil: Chicote, Gloria Beatriz. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

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Objetivos: Comprobar el efecto que tiene sobre el alumnado de Educación Primaria un programa de actividad física durante los recreos escolares mediante juegos pre-deportivos, en la composición corporal y en la condición física de los mismos. Metodología: Se realizó un análisis de las diferencias antes-después de muestras independientes de las pruebas de condición física y de las medidas antropométricas (grupo control y experimental), así como el valor de p de los contrastes, realizado mediante un análisis estadístico con el programa IBM SPSS 20.0. Aplicación a 54 alumnos y alumnas de Educación Primaria, de entre 9 y 11 años. Instrumentos: test de los 500 metros (resistencia); test de lanzamiento de balón medicinal (fuerza tren superior); test del salto horizontal (fuerza tren inferior); test de los 50 metros (velocidad); test de flexión profunda de tronco (flexibilidad). Resultados: Un estilo de vida activo, practicando actividad física diaria, se relaciona con mejoras en la condición física y en la composición corporal de sus practicantes. Conclusiones: Un programa de actividad física realizado en los recreos escolares con una duración de 30 minutos durante tres días a la semana, produce mejoras en los valores del IMC y la condición física de quien lo practica.

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Fil: Chicote, Gloria Beatriz. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

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Fil: Chicote, Gloria Beatriz. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.