EFFECTS OF FLOW STATES ON ELITE ATHLETES IN INVASION TEAM SPORTS: SYSTEMATIC REVIEW PROTOCOL

Review question / Objective: How does the flow state occur in invasion team sports (e.g., prevents; disrupts; restores; triggers; facilitates; hampers) and how does it influence the Elite athletes performance? Rationale: The flow state has been configured as an important flooring condition in the search for the best performance. However, there is an absence of systematizations about the flow state specifically in invasive team sports and its impact on performance. Therefore, it is relevant to qualify the types of studies conducted, their main correlations and causalities, as well as their main evidence and limitations. Condition being studied: The flow in invasion team sports and its impact on the Elite athletes performance.

Prograde and retrograde precession of a fluid-filled cylinder

We numerically study precession driven flows in a cylindrical container whose nutation angle varies between 60 and 90 degrees for prograde and retrograde precession. For prograde precession we observe sharp transitions between a laminar and a turbulent flow state with low and high geostrophic axisymmetric flow components related with a centrifugal instability, while for retrograde precession a rather smooth transition between a low state and a high state occurs. At the same time prograde and perpendicular precession shows an abrupt breakdown of the flow directly excited by the forcing mechanism, which is not the case for retrograde motion. We characterize the corresponding flow states in terms of the directly driven, non-axisymmetric Kelvin mode, the axisymmetric geostrophic mode, and an axisymmetric poloidal flow which is promising for precession-driven dynamo action. The latter issue is discussed with particular view on an optimal parameter choice for the DRESDYN dynamo project.

Perceptions About Flow and Boredom in the Information Technology Profession

This article aims to identify evidence of propensity for boredom and flow states among information technology (IT) professionals. A survey using the boredom proneness scale, Lee job boredom scale, and short flow scale resulted in 175 responses from professionals working in diverse IT activities. The main findings offer empirical evidence on the perception of IT professionals regarding (1) the occurrence of boredom and flow (even simultaneously), (2) highest occurrence of flow and boredom in the public sector, and (3) highest occurrence of boredom among younger IT professionals. This article offers relevant interpretations and contributions for theory and practice as it points out an emergent issue: IT professionals must also learn to deal with the routine and protocols of a maturing profession in order to meet industry standards, which interposes an unusual work situation for these professionals and their managers, since still prevail in the field the notions of a propensity for concentration to enjoy the task of coding and a willingness to face challenges, in a relaxed and funny way.

The Influence of Non-Newtonian Model on Properties of Blood Flow Through a Left Coronary Artery with Presence of Different Double Stenosis

Cardiovascular diseases were the main cause for loosing lives in the last decades due to the restricted blood flow states in the blood vessels areas. Numerical investigations have been conducted as the aim of this work to examine the blood flow, and wall shear stresses adjacent to the mono stenosis up to different degrees involved in the main, side and distal main branches as well as observe the pulsatile flow of blood in the left coronary artery through various percentage of stenosis. Both the Carreau non-Newtonian rheological model and the Newtonian model were utilized to model the blood fluid and wall shear stresses of left coronary artery, in a row, all the calculated data were validated with the previously published papers. It was found that the blood flow inside areas of the artery lie within the range of non-Newtonian rheological effects can be present, verifying the need to treat blood as non-Newtonian fluid; especially, with the case of 90% blockage.

Invasive validation of a novel approach to determine aortic valve area with phase-contrast cardiac magnetic resonance imaging

Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Austrian Society of Cardiology Background. Echocardiography is considered the standard method for screening and diagnosing aortic valve stenosis. However, inaccuracies in the determination of stroke-volumes by the continuity equation might particularly make the evaluation of patients with low-flow states difficult. Phase-contrast cardiac magnetic resonance (PC-CMR) is a promising tool in overcoming these limitations by the simultaneous determination of flow volumes and velocities across the stenotic valve. Purpose The aim of this study is to validate a novel approach based on PC-CMR against the invasive determination of the aortic valve area (AVA). Methods. PC-CMR was performed in 50 patients with moderate or severe AS (n = 52; age 72 years [interquartile range (IQR) 66 - 78], 38% of patients with low-flow states). All of them were referred to invasive evaluation of aortic stenosis by cardiac catheterization. Additionally, transthoracic echocardiography (TTE) was performed. Aortic valve area (AVA) was determined by PC-CMR (AVAPC-CMR) via plotting momentary flow across the valve against momentary flow velocity. AVAPC-CMR at different time points over the entire cardiac cycle was compared to invasively determined AVA, calculated according to the Gorlin-formula. Stroke volumes (SV) were determined by the Fick-principle, pressure gradients according to the modified Bernoulli-equation. Results. Mean AVA during the whole systolic phase showed a good correlation (r: 0.544, p < 0.001) with invasive AVA with a small bias (AVACMR: 0.78 cm², IQR: [0.60-0.96] versus AVAINVASIVE: 0.70 cm², IQR: [0.52-0.87], bias: 0.08 cm², p = 0.017). Intermethodical correlation and bias of AVA as measured by TTE (AVATTE) and AVAINVASIVE were similar to AVAPC-CMR (AVATTE: 0.81 cm²; IQR: [0.64-0.96] versus AVAINVASIVE: 0.70 cm², IQR: [0.52-0.87] r: 0.580, p < 0.001, bias 0.11 cm², p < 0.001). SV by PC-CMR showed a good correlation with Cine-CMR with no significant bias (r: 0.730, p < 0.001; SVPC-CMR: 86 ± 31 ml; SVCine: 85 ± 19 ml). Maximum gradients determined by PC‑CMR were 65 ± 2 9mmHg and showed a good inverse correlation with AVAPC-CMR (r: ‑0.371; p = 0.008). Conclusion. PC-CMR with continuous determination of flow volumes and flow velocities is able to determine AVA in patients with severe aortic stenosis with a tendency to overestimate AVA compared to invasively determined AVA.