8,159 research outputs found

    The effects of man-marking on work intensity in small-sided soccer games

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    The aim of this study was to examine the effect of manipulating defensive rules: with and without man-marking (MM and NMM) on exercise intensity in 3 vs. 3 small-sided games (SSGs). Twelve adolescent soccer players (age: 16.2 ± 0.7 years; body mass: 55.7 ± 6.4 kg; body height: 1.70 ± 0.07 m) participated in this repeated measures study. Each participant performed in four different SSGs formats: 3 vs. 3 MM with and without goals and 3 vs. 3 NMM with and without goals. Each SSG lasted 3 x 4 minutes interspersed with 4 minutes passive recovery. The percentage heart rate reserve (%HRreserve) was recorded continuously during SSG and session-rating of perceived exertion (session-RPE) after the SSG. MANOVA showed that defensive rule had significant effects on intensity (F = 5.37, p < 0.01). Specifically, MM during SSG induced significantly higher %HRreserve compared to NMM (Goal: 80.5 vs. 75.7%; No goal: 80.5 vs. 76.1%; p < 0.05, effect size = 0.91-1.06), irrespective of the presence or absence of goals. However, only MM with the presence of goals induced significant higher session-RPE compared to NMM (7.1 vs. 6.0; p < 0.05, effect size = 1.36), whereas no difference in session-RPE was observed between MM and NMM (7.4 vs. 6.9; p > 0.05, effect size = 0.63) when no goals were used. Higher intra-class reliability and lower coefficient of variation values were also reported in MM as compared to NMM. This study in youth soccer players shows there is ~4.5% increase in heart rate response by using the man-marking in 3 vs. 3 SSG thus the intensity of SSG can be significantly increased when using man-marking tactics

    An interference-aware virtual clustering paradigm for resource management in cognitive femtocell networks

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    Femtocells represent a promising alternative solution for high quality wireless access in indoor scenarios where conventional cellular system coverage can be poor. They are randomly deployed by the end user, so only post deployment network planning is possible. Furthermore, this uncoordinated deployment creates severe interference to co-located femtocells, especially in dense deployments. This paper presents a new architecture using a generalised virtual cluster femtocell (GVCF) paradigm, which groups together FAP into logical clusters. It guarantees severely interfering and overlapping femtocells are assigned to different clusters. Since each cluster operates on different band of frequencies, the corresponding virtual cluster controller only has to manage its own FAPs, so the overall system complexity is low. The performance of the GVCF algorithm is analysed from both a resource availability and cluster number perspective. Simulation results conclusively corroborate the superior performance of the GVCF model in interference mitigation, particularly in high density FAP scenarios

    Simultaneous removal of particles and dissolved organic matter in floating media filter for surface water treatment

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    This research investigated the performance of floating media filter in removing particles and dissolved organic matter from surface water. Pilot-scale study consists of floating plastic media pre-filter connected with either granular activated carbon (GAC) or sponge biological filter (BF) bed. In the floating plastic media filter, coagulation and flocculation processes using poly-aluminum chloride (PACl) as coagulant at an optimum dose of 8 mg/L helped removing particles from raw water. The floating media filter was operated a filtration rate of 11 m3/m2.h whereas those in GAC and BF units were maintained at 2 m3/m2.h. Continuous operation for over 120 days gave 98% and 99% average removal efficiencies of turbidity and UV254 in floating media filter in combination with GAC unit whereas and 78% and 52% removal efficiencies of turbidity and UV254 removal were obtained in floating media filter in combination with BF. The removal of dissolved organic carbon in GAC and BF units reduced chlorine demand for disinfection by 29% and 14%. It could also reduce the sum of trihalomethane (THMs) ratio from 1.1 to 0.1 and 0.5 respectively. © 2009 Desalination Publications

    Effect of flocculation and/or adsorption as pretreatment on the critical flux of crossflow microfiltration

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    This study aims at identifying the effect of pretreatment such as flocculation and/or adsorption on the performance of crossflow microfiltration (CFMF). CFMF performance was studied in terms of critical flux. The results indicated that: (1) flocculation alone as a pretreatment could effectively remove the large molecular weight organic matter from 30,000 to 60,000 Daltons; (2) flocculation, together with adsorption as a pretreatment to CFMF, could remove both large and small molecular weight organics; (3) flocculation as a pretreatment was significantly better than adsorption in improving the critical flux; (4) critical flux increased from 100 L/m2.h to 520 L/m2.h when flocculation-adsorption was applied. The critical flux in long-term experiments was the same as that of the short-term experiments. However, the critical flux slightly decreased (5%) in long-term experiments compared to short-term operation with flocculation and adsorption as a pretreatment. © 2005 Elsevier B.V. All rights reserved

    Trace element contents of selected antarctic meteorites, 1

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    Data are reported for volatile/mobile Ag, As, Au, Bi, Cd, Co, Cs, Cu, Ga, In, Rb, Sb, Se, Te, T1 and Zn in exterior and/or interior samples of four Antarctic meteorites: 77005 (unique achondrite); 77257 (unreilite); 77278 (L3); 77299 (H3). Exterior samples reflect contamination and/or leaching by weathering but trace element (ppm-ppt) contents in interior samples seem reasonable for representatives of these rare meteoritic types. The 77005 achondrite seems related to shergottites; other samples extend compositional ranges previously known for their types. With suitable precautions, Antarctic meteorite finds yield trace element data as reliable as those obtained from previously known falls

    Spatial correlations in chaotic nanoscale systems with spin-orbit coupling

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    We investigate the statistical properties of wave functions in chaotic nanostructures with spin-orbit coupling (SOC), focussing in particular on spatial correlations of eigenfunctions. Numerical results from a microscopic model are compared with results from random matrix theory in the crossover from the gaussian orthogonal to the gaussian symplectic ensembles (with increasing SOC); one- and two-point distribution functions were computed to understand the properties of eigenfunctions in this crossover. It is found that correlations of wave function amplitudes are suppressed with SOC; nevertheless, eigenfunction correlations play a more important role in the two-point distribution function(s), compared to the case with vanishing SOC. Experimental consequences of our results are discussed.Comment: Submitted to PR

    The Effects of Mergers and Acquisitions on Acquiring Banks’ Contribution to Systemic Risk

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    This paper is the first to examine the effects of international bank mergers and acquisitions on acquirers' contribution to systemic risk covering the period from 1998 to 2015. Our sample consists of 608 international bank mergers, involved domestic and cross-border deals as well as conglomerate and non-conglomerate mergers. Using the Marginal Expected Shortfall (as in Acharya et al., 2017) as well as Conditional Value-at-Risk (as in Adrian and Brunnermeier, 2016) as systemic risk measurements, we find that on average, mergers do not impact on the acquiring banks’ contribution to systemic risk regardless of the increased potential for risk diversification exhibited by cross-border and cross-industry bank mergers. Determinants that contributes to the decrease in acquirers’ systemic risk include product diversifying deals, deals conducted in a more concentrated banking system and a stable political environment. Whereas, for deals financed by cash only and much smaller compared to acquirers as well as involved private targets, acquirers' contribution to systemic risk increase after the merger

    Large-scale chaos and fluctuations in active nematics

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    We show that "dry" active nematics, e.g. collections of shaken elongated granular particles, exhibit large-scale spatiotemporal chaos made of interacting dense, ordered, band-like structures in a parameter region including the linear onset of nematic order. These results are obtained from the study of the relatively simple and well-known (deterministic) hydrodynamic equations describing these systems in a dilute limit, and of a self-propelled particle Vicsek-like model for this class of active matter. In this last case, revisiting the status of the strong fluctuations and long-range correlations now considered as landmarks of orientationally-ordered active phases, we show that the giant number fluctuations observed in the chaotic phase are a trivial consequence of density segregation. However anomalous density fluctuations are present in the homogeneous quasi-ordered nematic phase and characterized by a non-trivial scaling exponent
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