Do the kinematics of a baulked take-off in springboard diving differ from those of a completed dive

Consistency and invariance in movements are traditionally viewed as essential features of skill acquisition and elite sports performance. This emphasis on the stabilization of action has resulted in important processes of adaptation in movement coordination during performance being overlooked in investigations of elite sport performance. Here we investigate whether differences exist between the movement kinematics displayed by five, elite springboard divers (age 17 ± 2.4 years) in the preparation phases of baulked and completed take-offs. The two-dimensional kinematic characteristics of the reverse somersault take-off phases (approach and hurdle) were recorded during normal training sessions and used for intra-individual analysis. All participants displayed observable differences in movement patterns at key events during the approach phase; however, the presence of similar global topological characteristics suggested that, overall, participants did not perform distinctly different movement patterns during completed and baulked dives. These findings provide a powerful rationale for coaches to consider assessing functional variability or adaptability of motor behaviour as a key criterion of successful performance in sports such as diving.

Self-organization processes in field-invasion team sports

In nature, the interactions between agents in a complex system (fish schools; colonies of ants) are governed by information that is locally created. Each agent self-organizes (adjusts) its behaviour, not through a central command centre, but based on variables that emerge from the interactions with other system agents in the neighbourhood. Self-organization has been proposed as a mechanism to explain the tendencies for individual performers to interact with each other in field-invasion sports teams, displaying functional co-adaptive behaviours, without the need for central control. The relevance of self-organization as a mechanism that explains pattern-forming dynamics within attacker-defender interactions in field-invasion sports has been sustained in the literature. Nonetheless, other levels of interpersonal coordination, such as intra-team interactions, still raise important questions, particularly with reference to the role of leadership or match strategies that have been prescribed in advance by a coach. The existence of key properties of complex systems, such as system degeneracy, nonlinearity or contextual dependency, suggests that self-organization is a functional mechanism to explain the emergence of interpersonal coordination tendencies within intra-team interactions. In this opinion article we propose how leadership may act as a key constraint on the emergent, self-organizational tendencies of performers in field-invasion sports.

Performance analysis in team sports : advances from an ecological dynamics approach

Capacity to produce data for performance analysis in sports has been enhanced in the last decade with substantial technological advances. However, current performance analysis methods have been criticised for the lack of a viable theoretical framework to assist on the development of fundamental principles that regulate performance achievement. Our aim in this paper is to discuss ecological dynamics as an explanatory framework for improving analysis and understanding of competitive performance behaviours. We argue that integration of ideas from ecological dynamics into previous approaches to performance analysis advances current understanding of how sport performance emerges from continuous interactions between individual players and teams. Exemplar data from previous studies in association football are presented to illustrate this novel perspective on performance analysis. Limitations of current ecological dynamics research and challenges for future research are discussed in order to improve the meaningfulness of information presented to coaches and managers.

How small-sided and conditioned games enhance acquisition of movement and decision-making skills

This article summarizes research from an ecological dynamics program of work on team sports exemplifying how small-sided and conditioned games (SSCG) can enhance skill acquisition and decision-making processes during training. The data highlighted show how constraints of different SSCG can facilitate emergence of continuous interpersonal coordination tendencies during practice to benefit team game players.

Competing together : assessing the dynamics of team-team and player-team synchrony in professional association football

This study investigated movement synchronization of players within and between teams during competitive association football performance. Cluster phase analysis was introduced as a method to assess synchronies between whole teams and between individual players with their team as a function of time, ball possession and field direction. Measures of dispersion (SD) and regularity (sample entropy – SampEn – and cross sample entropy – Cross-SampEn) were used to quantify the magnitude and structure of synchrony. Large synergistic relations within each professional team sport collective were observed, particularly in the longitudinal direction of the field (0.89 ± 0.12) compared to the lateral direction (0.73 ± 0.16, p < .01). The coupling between the group measures of the two teams also revealed that changes in the synchrony of each team were intimately related (Cross-SampEn values of 0.02 ± 0.01). Interestingly, ball possession did not influence team synchronization levels. In player–team synchronization, individuals tended to be coordinated under near in-phase modes with team behavior (mean ranges between −7 and 5° of relative phase). The magnitudes of variations were low, but more irregular in time, for the longitudinal (SD: 18 ± 3°; SampEn: 0.07 ± 0.01), compared to the lateral direction (SD: 28 ± 5°; SampEn: 0.06 ± 0.01, p < .05) on-field. Increases in regularity were also observed between the first (SampEn: 0.07 ± 0.01) and second half (SampEn: 0.06 ± 0.01, p < .05) of the observed competitive game. Findings suggest that the method of analysis introduced in the current study may offer a suitable tool for examining team’s synchronization behaviors and the mutual influence of each team’s cohesiveness in competing social collectives.

Reluctantly virtual : modelling copyright industry dynamics

During the evolution of the music industry, developments in the media environment have required music firms to adapt in order to survive. Changes in broadcast radio programming during the 1950s; the Compact Cassette during the 1970s; and the deregulation of media ownership during the 1990s are all examples of changes which have heavily affected the music industry. This study explores similar contemporary dynamics, examines how decision makers in the music industry perceive and make sense of the developments, and reveals how they revise their business strategies, based on their mental models of the media environment. A qualitative system dynamics model is developed in order to support the reasoning brought forward by the study. The model is empirically grounded, but is also based on previous music industry research and a theoretical platform constituted by concepts from evolutionary economics and sociology of culture. The empirical data primarily consist of 36 personal interviews with decision makers in the American, British and Swedish music industrial ecosystems. The study argues that the model which is proposed, more effectively explains contemporary music industry dynamics than music industry models presented by previous research initiatives. Supported by the model, the study is able to show how “new” media outlets make old music business models obsolete and challenge the industry’s traditional power structures. It is no longer possible to expose music at one outlet (usually broadcast radio) in the hope that it will lead to sales of the same music at another (e.g. a compact disc). The study shows that many music industry decision makers still have not embraced the new logic, and have not yet challenged their traditional mental models of the media environment. Rather, they remain focused on preserving the pivotal role held by the CD and other physical distribution technologies. Further, the study shows that while many music firms remain attached to the old models, other firms, primarily music publishers, have accepted the transformation, and have reluctantly recognised the realities of a virtualised environment.

Recasting the theory of mosquito-borne pathogen transmission dynamics and control

Mosquito-borne diseases pose some of the greatest challenges in public health, especially in tropical and sub-tropical regions of theworld. Efforts to control these diseases have been underpinned by a theoretical framework developed for malaria by Ross and Macdonald, including models, metrics for measuring transmission, and theory of control that identifies key vulnerabilities in the transmission cycle. That framework, especially Macdonald’s formula for R0 and its entomological derivative, vectorial capacity, are nowused to study dynamics and design interventions for many mosquito-borne diseases. A systematic review of 388 models published between 1970 and 2010 found that the vast majority adopted the Ross–Macdonald assumption of homogeneous transmission in a well-mixed population. Studies comparing models and data question these assumptions and point to the capacity to model heterogeneous, focal transmission as the most important but relatively unexplored component in current theory. Fine-scale heterogeneity causes transmission dynamics to be nonlinear, and poses problems for modeling, epidemiology and measurement. Novel mathematical approaches show how heterogeneity arises from the biology and the landscape on which the processes of mosquito biting and pathogen transmission unfold. Emerging theory focuses attention on the ecological and social context formosquito blood feeding, themovement of both hosts and mosquitoes, and the relevant spatial scales for measuring transmission and for modeling dynamics and control.

A distributed control based coordination scheme of household PV systems for overvoltage prevention

This paper presents a distributed communication based active power curtailment (APC) control scheme for grid connected photovoltaic (PV) systems to address voltage rise. A simple distribution feeder model is presented and simulated using MATLAB. The resource sharing based control scheme proposed is shown to be effective at reducing voltage rise during times of peak generation and low load. Simulations also show the even distribution of APC using simple communications. Simulations demonstrate the versatility of the proposed control method under major communication failure conditions. Further research may lead to possible applications in coordinated electric vehicle (EV) charging.

Introducing dynamics : a new approach to "new media" [Editorial]

The term ‘‘new media’’ has been in play for decades now, and one might be forgiven for wondering how much longer digital forms and platforms can really be called ‘‘new,’’ or even what the scholarship of new media contributes to knowledge. Is it possible to say new things about new media? We think so. This Companion not only demonstrates the variety, salience, and importance of new media studies but also proposes a distinctive approach to the topic : an approach we call ‘‘new media dynamics.’’ In this view, what’s interesting about ‘‘new media’’ is not novelty as such but dynamism. Capitalism, technology, social networks, and media all evolve and change, sometimes to our delight, sometimes our dismay. This incessant process of disruption, renewal, and eventual (if often partial) replacement is now one of humanity’s central experiences. This cutting-edge collection brings together a stellar array of the world’s top researchers, cultural entrepreneurs, and emerging scholars to give the dynamics of new media their first full-length, multidisciplinary, historical, and critical treatment. Across 34 chapters, an international line-up of the very best authors reflects on the historical, technical, cultural, and political changes that underlie the emergence of new media, as existing patterns and assumptions are challenged by the forces of ‘‘creative destruction’’ and innovation, both economic and cultural. At the same time they show that familiar themes and problems carry through from ‘‘old’’media – questions of identity, sexuality, politics, relationships, and meaning.

A nation’s role in addressing base erosion and profit shifting : balancing sovereignty with international collaboration and coordination

The notion of sovereignty is central to any international tax issue. While a nation is free to design its tax laws as it sees fit and raise revenue in accordance with the needs of its citizens, it is not possible to undertake such a task in isolation. In a world of cross-border investments and business transactions, all tax regimes impact on one another. Tax interactions between sovereign states cannot be avoided. Ultimately, the interactions mean that a nation must decide whether to engage in both collaboration and coordination with other nations and supranational bodies alike or maintain an individualised stance in relation to its tax policy. Whatever the decision, there is arguably an exercise in national sovereignty in some form. In the context of an international tax regime, whether that regime is interpreted broadly as meaning international norms generally adopted by nations around the world or domestic regimes legislating for cross-border transactions, rhetoric around national fiscal sovereignty takes on many different forms. At one end of the spectrum it is relied upon by financial secrecy jurisdictions (tax havens) as a defence to their position on the basis that ‘other’ nations cannot interfere with the fiscal sovereignty of a jurisdiction. At the other end of the spectrum, it is argued that profit shifting and international tax avoidance if not stopped is, in and of itself, a threat to a nation’s fiscal sovereignty on the basis that it threatens the ability to tax and raise the revenue needed. This paper considers a modern conceptualisation of sovereignty along with its role within international tax coordination and collaboration to argue that a move towards a more unified approach to addressing international base erosion and profit shifting may be the ultimate exercise of national fiscal sovereignty. By using the current transfer pricing regime as a case study, this paper posits that it is not merely enough to have international agreement on allocation rules to be applied, but that the ultimate exercise of national sovereignty is political agreement with other states to ensure that it is governments which determine the allocational basis of worldwide profits to be taxed. In doing so, it is demonstrated that the arm’s length pricing requirement of the current transfer pricing regime, rather than providing governments with the ability to determine the location of profits, is providing multinational entities with the ultimate power to determine that location. If left unchecked, this will eventually erode a nation’s ability to capture the required tax revenue and, as a consequence, may be deemed a failure by nation states to exercise their fiscal sovereignty.

Impact of passenger group dynamics on an airport evacuation process using an agent-based model

The safety of passengers is a major concern to airports. In the event of crises, having an effective and efficient evacuation process in place can significantly aid in enhancing passenger safety. Hence, it is necessary for airport operators to have an in-depth understanding of the evacuation process of their airport terminal. Although evacuation models have been used in studying pedestrian behaviour for decades, little research has been done in considering the evacuees’ group dynamics and the complexity of the environment. In this paper, an agent-based model is presented to simulate passenger evacuation process. Different exits were allocated to passengers based on their location and security level. The simulation results show that the evacuation time can be influenced by passenger group dynamics. This model also provides a convenient way to design airport evacuation strategy and examine its efficiency. The model was created using AnyLogic software and its parameters were initialised using recent research data published in the literature.

Exploring board dynamics : director participation during board meetings

Despite board meetings representing the main arena where directors discharge their duties and make critical corporate decisions, we know little about what occurs in the boardroom. Consequently, there is increasing academic interest in understanding how meetings are run and how directors participate. This study contributes to this emerging literature by exploring the impact of board meeting arrangements on directors’ interactions and perceptions of meeting effectiveness. We video-taped board meetings at two Australian corporations operating in the same industry and use an in-depth analysis of interactions and board processes to reveal that a rather small difference in meeting arrangements (i.e. the timing and length of meetings) had a significant influence on interaction patterns. Specifically, given significant amounts of environmental turbulence in the sector, director inclusiveness and participation were reduced as time pressure increased due to shorter meetings, lowering director perceptions of meeting effectiveness.

Dynamics of affordances and implications for design

Affordance is an important concept in HCI. There are various interpretations of affordances but it has been difficult to use this concept for design purposes. Often the treatment of affordances in the current HCI literature has been as a one-to-one relationship between a user and an artefact. According to our views, affordance is a dynamic, always emerging relationship between a human and his environment. We believe that the social and cultural contexts within which an artefact is situated affect the way in which the artefact is used. Using a Structuration Theory approach, we argue that affordances need also be treated at a much broader level, encompassing social and cultural aspects. We suggest that affordances should be seen at three levels: single user, organizational (or work group) and societal. Focusing on the organizational level affordances, we provide details of several important factors that affect the emergence of affordances.

Molecular dynamics simulation of mechanical behavior of osteopontin-hydroxyapatite interfaces

Bone is characterized with an optimized combination of high stiffness and toughness. The understanding of bone nanomechanics is critical to the development of new artificial biological materials with unique properties. In this work, the mechanical characteristics of the interfaces between osteopontin (OPN, a noncollagenous protein in extrafibrillar protein matrix) and hydroxyapatite (HA, a mineral nanoplatelet in mineralized collagen fibrils) were investigated using molecular dynamics method. We found that the interfacial mechanical behaviour is governed by the electrostatic attraction between acidic amino acid residues in OPN and calcium in HA. Higher energy dissipation is associated with the OPN peptides with a higher number of acidic amino acid residues. When loading in the interface direction, new bonds between some acidic residues and HA surface are formed, resulting in a stick-slip type motion of OPN peptide on the HA surface and high interfacial energy dissipation. The formation of new bonds during loading is considered to be a key mechanism responsible for high fracture resistance observed in bone and other biological materials.