Team sports performance analysed through the lens of social network theory: implications for research and practice

This paper discusses how social network analyses and graph theory can be implemented in team sports performance analyses to evaluate individual (micro) and collective (macro) performance data, and how to use this information for designing practice tasks. Moreover, we briefly outline possible limitations of social network studies and provide suggestions for future research. Instead of cataloguing discrete events or player actions, it has been argued that researchers need to consider the synergistic interpersonal processes emerging between teammates in competitive performance environments. Theoretical assumptions on team coordination prompted the emergence of innovative, theoretically-driven methods for assessing collective team sport behaviours. Here, we contribute to this theoretical and practical debate by conceptualising sports teams as complex social networks. From this perspective, players are viewed as network nodes, connected through relevant information variables (e.g., a ball passing action), sustaining complex patterns of interaction between teammates (e.g., a ball passing network). Specialized tools and metrics related to graph theory could be applied to evaluate structural and topological properties of interpersonal interactions of teammates, complementing more traditional analysis methods. This innovative methodology moves beyond use of common notation analysis methods, providing a richer understanding of the complexity of interpersonal interactions sustaining collective team sports performance. The proposed approach provides practical applications for coaches, performance analysts, practitioners and researchers by establishing social network analyses as a useful approach for capturing the emergent properties of interactions between players in sports teams

Theory to Practice: Performance Preparation Models in Contemporary High-Level Sport Guided by an Ecological Dynamics Framework

Abstract: A fundamental challenge for practitioners in high-level sporting environments concerns how to support athletes in adapting behaviours to solve emergent problems during competitive performance. Guided by an ecological dynamics framework, the design and integration of competitive performance preparation models that place athlete-environment interactions at the heart of the learning process may address this challenge. This ecological conceptualisation of performance preparation signifies a shift in a coach’s role; evolving from a consistent solution provider to a learning environment designer who fosters local athlete-environment interactions. However, despite the past decades of research within the ecological dynamics framework developing an evidence-based, theoretical conceptualisation of skill acquisition, expertise and talent development, an ongoing challenge resides within its practical integration into sporting environments. This article provides two case examples in which high-level sports organisations have utilised an ecological dynamics framework for performance preparation in Australian football and Association Football. A unique perspective is offered on experiences of professional sport organisations attempting to challenge traditional ideologies for athlete performance preparation by progressing the theoretical application of ecological dynamics. These case examples intend to promote the sharing of methodological ideas to improve athlete development, affording opportunities for practitioners and applied scientists to accept, reject or adapt the approaches presented here to suit their specific ecosystems

In situ detection of Chlamydia pneumoniae, C. trachomatis, and cytokines among cardiovascular diseased patients from the Amazon region of Brazil

Larissa S Freitas,1 Núbia Caroline C Almeida,1 Maria Alice Freitas Queiroz,1 Marcelo M Zaninotto,2 Hellen T Fuzii,3 Alfredo Ribeiro-Silva,4 Antonio CR Vallinoto,1 Marluísa OG Ishak,1 Juarez AS Quaresma,3 Ricardo Ishak1 1Virus Laboratory, Institute of Biological Sciences, Federal University of Para, 2Hospital of Clinic Gaspar Viana, 3Laboratory of Immunopathology, Nucleus of Tropical Medicine, Federal University of Para, Belém, 4Departament of Pathology, Medical School of Ribeirão Preto, University of Sao Paulo, São Paulo, Brazil Background: Chronic coronary artery disease has been associated, as a consequence of the local inflammatory reaction with previous or persistent infection with Chlamydia pneumoniae, which led to the investigation of the association of cardiovascular disease and previous infection with C. trachomatis and the role of cytokine profile (in situ) markers in the vascular system tissues. Methods: Sixty-nine biopsies were collected for immunohistochemical analysis for the presence of IL-6, IL-8, TNF-α, IFN-γ, TGF-β, and IL-10, in 16 fragments from atheromatous plaques, 32 aorta fragments, and 21 valve fragments, using a tissue microarray technique for paraffin embedded tissues. Results: Most patients undergoing revascularization surgery were men >50 years, while those undergoing valve replacement were mostly women <50 years. TNF-α was the most prevalent marker, detected in 91.7% (55/60) of the samples. The mean percent area stained was greater in patients infected with C. pneumoniae (3.81% vs 1.92%; p=0.0115) and specifically in the aorta (4.83% vs 2.25%; p=0.0025); C. trachomatis infection was higher in valves, and C. pneumoniae in plaques, both without statistical significance. There was no significant difference in the cytokine staining profile between patients previously infected with both species and uninfected patients. Conclusion: Although there was no difference in the cytokine profile between patients previously infected with both species of Chlamydia, and uninfected patients, the presence of the bacteria antigens in the three biological specimens indicates it is important to focus on the role of C. trachomatis. It is necessary to improve the understanding of the natural history of chronic coronary artery disease and the clinical history of the patients and cytokine dynamics in cardiac disease in the presence or absence of infectious agents. Keywords: Chlamydia, C. pneumoniae, C. trachomatis, atherosclerosis, cytokine

Performance of a Venturi scrubber in the removal of fine powder from a confined gas stream

Experimental results on the performance of a laboratory scale rectangular Venturi scrubber in the removal of fine mineral particles from a confined air stream are presented, and a new correlation is proposed and evaluated. The scrubber was operated with air velocities in the throat varying from 58 m/s to 75 m/s and liquid flow rates varying from 280 ml/min to 900 ml/min. Liquid was injected as a jet emerging from a 1.0 mm orifice at the throat. Results for dust collection grade efficiency varied from 87% to 98% for particles from 0.1 µm to 2.0 µm