| 1 | PM_(2.5) source apportionment in a French urban coastal site under steelworks emission influences using constrained non-negative matrix factorization receptor model显示文摘The constrained weighted-non-negative matrix factorization(CW-NMF) hybrid receptor model was applied to study the influence of steelmaking activities on PM_(2.5)(particulate matter with equivalent aerodynamic diameter less than 2.5 μm) composition in Dunkerque,Northern France. Semi-diurnal PM_(2.5)samples were collected using a high volume sampler in winter 2010 and spring 2011 and were analyzed for trace metals, water-soluble ions, and total carbon using inductively coupled plasma – atomic emission spectrometry(ICP-AES),ICP- mass spectrometry(ICP-MS), ionic chromatography and micro elemental carbon analyzer. The elemental composition shows that NO_3^-, SO_4^(2-), NH_4^+and total carbon are the main PM_(2.5)constituents. Trace metals data were interpreted using concentration roses and both influences of integrated steelworks and electric steel plant were evidenced. The distinction between the two sources is made possible by the use Zn/Fe and Zn/Mn diagnostic ratios. Moreover Rb/Cr, Pb/Cr and Cu/Cd combination ratio are proposed to distinguish the ISW-sintering stack from the ISW-fugitive emissions. The a priori knowledge on the influencing source was introduced in the CW-NMF to guide the calculation. Eleven source profiles with various contributions were identified: 8 are characteristics of coastal urban background site profiles and 3 are related to the steelmaking activities. Between them,secondary nitrates, secondary sulfates and combustion profiles give the highest contributions and account for 93% of the PM_(2.5)concentration. The steelwork facilities contribute in about 2%of the total PM_(2.5)concentration and appear to be the main source of Cr, Cu, Fe, Mn, Zn. | Adib Kfoury Frederic Ledoux Cloe Roche Gilles Delmaire Gilles Roussel Dominique Courcot | 2016 | Journal of Environmental Sciences2016，28，2： | 3 |
| 4 | Post-exercise heart rate variability recovery after 800-m endurance run load among Cameroonian adolescent's males显示文摘The 800-m(m)run is part of Physical Education classes in Cameroon,after which arrhythmias may occur during recovery.Hence,this study aimed at determining relationship between 800-m run loads on cardiac autonomic recovery among school adolescents.Forty-two male adolescents(aged[17-1]years)performed 800-m.Post-exercise heart rate variability(HRV)was recorded during 5-min(min)(HRV5-min)and 15-min(HRV15-min)in time:Standard deviation of normal to normal(SDNN);Root mean square of successive differences(RMSSD)and frequency domain(LH:Low frequency,HF:High frequency,TP:Total power).Rating of Perceived Exertion(RPE)and blood lactate concentration(BLa)were measured after exercise.In HRV5-min,RPE was associated with SDNN(r=-0.44,p<0.01)and RMSSD(r=-0.38,p<0.05).BLa was correlated with SDNN(r=-0.38,p<0.05)and RMSSD(r=-0.56,p<0.001)in the time-domain,LF(r=-0.64,p<0.001),HF(r=-0.58,p<0.001)and TP(r=-0.61,p<0.001)in frequencydomain.Moreover,RPE was correlated with LF(r=-0.44,p<0.01),TP(r=-0.49,p<0.01)while exercise duration with HF(r=-0.38,p<0.05).In HRV15-min,BLa was correlated with RMSSD(r=-0.53,p<0.001)and SDNN(r=-0.68,p<0.001).RPE was negatively correlated SDNN(r=-0.53,p<0.01)and RMSSD(r=-0.44,p<0.01).BLa was associated with HF(r=-0.55,p<0.001),TP(r=-0.50,p<0.01)and RPE with LF(r=-0.51,p<0.01),HF(r=-0.50,p<0.01),TP(r=-0.49,p<0.01).In addition,exercise duration was negatively linked to HF(r=-0.36,p<0.05).This study outlined that in untrained adolescents an increase of 800-m loads is associated with a slow vagal indexes of HRV during the recovery. | Jerson Mekoulou Ndongo Elysee Claude Bika Lele Wiliam Richard Guessogo Wiliam Mbang Mbian Clarisse Noel Ayina Ayina Jessica Guyot Christian Ngongang Ouankou Abdou Temfemo Loick Pradel Kojom Foko Ernest Tchoudjin Louis-Georges Gassina Bienvenu Bongue Frederic Roche Samuel Honore Mandengue Peguy Brice Assomo-Ndemba | 2023 | Sports Medicine and Health Science2023，5，4： | 0 |
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