FOOT-TO-BALL INTERACTION IN PREFERRED AND NON-PREFERRED LEG AUSTRALIAN RULES KICKING

Kicking is an integral skill within Australian Rules Football (ARF) and the ability to kick with either foot is essential at the elite level. A principal technical factor in the kicking skill is the nature of impact between the kicking foot and ball (Ball, 2008a). This study compared characteristics of foot-to-ball interaction between preferred and non-preferred kicking legs in Australian Rules football (ARF). Eighteen elite ARF players performed a maximum distance kick on their preferred and non-preferred legs. From high-speed video (6000Hz), two-dimensional digitised data of seven points (five on the kick leg, two on the ball) were used to quantify parameters near and during impact. The preferred foot produced significantly larger foot speed, ball speed, work done on the ball, ball displacement while in contact with the foot and change in shank angle during the ball contact phase

KICK IMPACT CHARACTERISTICS OF JUNIOR KICKERS

Impact is important to kicking performance and while differences have been found between kick distances and between preferred and non-preferred leg kicks, no work has examined junior kickers. This study examined impact characteristics of the Australian football (AF) drop punt kick for juniors and compared these data with seniors from Smith et al. (2009). Twenty one junior AF players performed a maximum distance kick. The foot, ball and shank were digitised from 6000 Hz video to calculate seven foot/ball parameters. Junior players produced significantly smaller foot and ball speeds but not foot to ball speed ratios compared to senior players. Work was also significantly different due to lesser force being applied to the ball. Junior players should focus on increasing foot speed and force on the ball to increase kick distance

Bosonic behavior of entangled fermions

Two bound, entangled fermions form a composite boson, which can be treated as an elementary boson as long as the Pauli principle does not affect the behavior of many such composite bosons. The departure of ideal bosonic behavior is quantified by the normalization ratio of multi-composite-boson states. We derive the two-fermion-states that extremize the normalization ratio for a fixed single-fermion purity P, and establish general tight bounds for this indicator. For very small purities, P<1/N^2, the upper and lower bounds converge, which allows to quantify accurately the departure from perfectly bosonic behavior, for any state of many composite bosons.Comment: 9 pages, 5 figures, accepted by PR

The referee's challenge: a threshold process model for decision making in sport games

Judgment and decision making in sporting officials is a challenging task that involves the use of context. Although process models of decision making describe decision contexts, none of the existing models explains when sports officials use rule-driven decision making, or game management. The basic idea of our work is that referees use a subjective threshold to apply game management, which may explain this decision behavior. We propose a new dynamic threshold model that is based on concepts derived from Decision Field Theory (Busemeyer & Townsend, 1993). The model includes two thresholds of game management (high/low) and two contact situations (foul/no foul) as approaching one of these thresholds. Using the example of soccer refereeing, we argue that if the game hits a subjective threshold of aggressive play, then the referee shifts from applying the rules to managing the game. This new approach changes the scientific discussion from one focused on what referees should decide in one situation or the other, to a dynamic model that explains the basic psychological mechanism underlying the referee’s change in behavior during the game, both at the intra-individual as well as inter-individual leve

Does framing the hot hand belief change decision-making behavior in volleyball?

PURPOSE: Previous discussions of the hot hand belief, wherein athletes believe that they have a greater chance of scoring after 2 or 3 hits (successes) compared with 2 or 3 misses, have focused on whether this is the case within game statistics. Researchers have argued that the perception of the hot hand in random sequences is a bias of the cognitive system. Yet most have failed to explore the impact of framing on the stability of the belief and the behavior based on it. METHOD: The authors conducted 2 studies that manipulated the frame of a judgment task. In Study 1, framing was manipulated via instructions in a playmaker allocation paradigm in volleyball. In Study 2, the frame was manipulated by presenting videos for allocation decisions from either the actor or observer perspective. RESULTS: Both manipulations changed the hot hand belief and sequential choices. We found in both studies that the belief in continuation of positive or negative streaks is nonlinear and allocations to the same player after 3 successive hits are reduced. CONCLUSIONS: The authors argue that neither the hot hand belief nor hot hand behavior is stable, but rather, both are sensitive to decision frames. The results can inform coaches on the importance of how to provide information to athletes

Prior events predict cerebrovascular and coronary outcomes in the PROGRESS trial

&lt;p&gt;&lt;b&gt;Background and Purpose:&lt;/b&gt; The relationship between baseline and recurrent vascular events may be important in the targeting of secondary prevention strategies. We examined the relationship between initial event and various types of further vascular outcomes and associated effects of blood pressure (BP)–lowering.&lt;/p&gt; &lt;p&gt;&lt;b&gt;Methods:&lt;/b&gt; Subsidiary analyses of the Perindopril Protection Against Recurrent Stroke Study (PROGRESS) trial, a randomized, placebo-controlled trial that established the benefits of BP–lowering in 6105 patients (mean age 64 years, 30% female) with cerebrovascular disease, randomly assigned to either active treatment (perindopril for all, plus indapamide in those with neither an indication for, nor a contraindication to, a diuretic) or placebo(s).&lt;/p&gt; &lt;p&gt;&lt;b&gt;Results:&lt;/b&gt; Stroke subtypes and coronary events were associated with 1.5- to 6.6-fold greater risk of recurrence of the same event (hazard ratios, 1.51 to 6.64; P=0.1 for large artery infarction, P&#60;0.0001 for other events). However, 46% to 92% of further vascular outcomes were not of the same type. Active treatment produced comparable reductions in the risk of vascular outcomes among patients with a broad range of vascular events at entry (relative risk reduction, 25%; P&#60;0.0001 for ischemic stroke; 42%, P=0.0006 for hemorrhagic stroke; 17%, P=0.3 for coronary events; P homogeneity=0.4).&lt;/p&gt; &lt;p&gt;&lt;b&gt;Conclusions:&lt;/b&gt; Patients with previous vascular events are at high risk of recurrences of the same event. However, because they are also at risk of other vascular outcomes, a broad range of secondary prevention strategies is necessary for their treatment. BP–lowering is likely to be one of the most effective and generalizable strategies across a variety of major vascular events including stroke and myocardial infarction.&lt;/p&gt

BIOMECHANICAL ANALYSIS OF THE HANDBALL IN AUSTRALIAN FOOTBALL

The handball pass in Australian Football has become increasingly important in recent years. However, important technical elements of handballing have not been identified in the scientific literature. The purposes of this study were to provide a descriptive analysis of the handball through the evaluation of a player considered to have good technique, to compare handballs for maximal speed and accuracy, and to compare preferred and non-preferred hands. Three-dimensional data were collected from one elite level Australian Football player using Optotrak Certus. The player performed three handballs for maximal speed and three handballs for accuracy with both the preferred and non-preferred hand. Linear hand speed, linear shoulder speed, shoulder angular velocity and elbow angular velocity were larger in the maximal speed condition. Differences in the development of hand speed were found for preferred and non-preferred hands

Herbivorous mammals along a montane sere: Community structure and energetics

All common herbivorous mammals were censused along a successional gradient in northern Utah in order to assess some of the changes in ecosystem attributes predicted to occur by Odum (1969). Biomass (B) and energy flow [Production (P), Respiration (R), and P + R (E)] through each of nine species in each of four seral stages (montane meadow, Populus-dominated forest, Abies-dominated forest, and Picea-dominated forest) were estimated. Tests of eight predicted trends were supportwe in five cases (P/R ratio, P/B ratio, B/E ratio, net community production, and species richness), inconsistent in two cases (total organic matter and species evenness/general diversity) and ambiguous in one (size of organism). Community stability, as measured by changes in average community biomass between years of relatively normal and extremely low precipitation, increased with ecosystem maturity. Individual species, however, fluctuated greatly in biomass between the 2 years. Our results are consistent with the hypothesis that mammals are determinants of successional patterns only insofar as they affect plant colonization. However, a continuum probably exists between completely passive species and those that strongly influence successional patterns in plant communities through their effects on plant recruitment and/or mortality. Changes in the plant community in turn affect the composition of the herbivorous mammal community

Commensal observing with the Allen Telescope array: software command and control

The Allen Telescope Array (ATA) is a Large-Number-Small-Diameter radio telescope array currently with 42 individual antennas and 5 independent back-end science systems (2 imaging FX correlators and 3 time domain beam formers) located at the Hat Creek Radio Observatory (HCRO). The goal of the ATA is to run multiple back-ends simultaneously, supporting multiple science projects commensally. The primary software control systems are based on a combination of Java, JRuby and Ruby on Rails. The primary control API is simplified to provide easy integration with new back-end systems while the lower layers of the software stack are handled by a master observing system. Scheduling observations for the ATA is based on finding a union between the science needs of multiple projects and automatically determining an efficient path to operating the various sub-components to meet those needs. When completed, the ATA is expected to be a world-class radio telescope, combining dedicated SETI projects with numerous radio astronomy science projects.Comment: SPIE Conference Proceedings, Software and Cyberinfrastructure for Astronomy, Nicole M. Radziwill; Alan Bridger, Editors, 77400Z, Vol 774

Professor C. N. Yang and Statistical Mechanics

Professor Chen Ning Yang has made seminal and influential contributions in many different areas in theoretical physics. This talk focuses on his contributions in statistical mechanics, a field in which Professor Yang has held a continual interest for over sixty years. His Master's thesis was on a theory of binary alloys with multi-site interactions, some 30 years before others studied the problem. Likewise, his other works opened the door and led to subsequent developments in many areas of modern day statistical mechanics and mathematical physics. He made seminal contributions in a wide array of topics, ranging from the fundamental theory of phase transitions, the Ising model, Heisenberg spin chains, lattice models, and the Yang-Baxter equation, to the emergence of Yangian in quantum groups. These topics and their ramifications will be discussed in this talk.Comment: Talk given at Symposium in honor of Professor C. N. Yang's 85th birthday, Nanyang Technological University, Singapore, November 200