Effects of school soccer training on the health and fitness of obese children / Efeitos do treinamento de futebol escolar sobre a saúde e a aptidão física de crianças obesas / Efectos del entrenamiento de fútbol escolar en la salud y la aptitud física de niños obesos

ABSTRACT Introduction Based on the representative data reflecting the level of physical development and athletic quality, such as the "National Physical Health Test for Students", it is shown that the physical health status of adolescents and children in China is decreasing annually, and the trend of obesity is gradually increasing. Objective Analyze and study the effect of training on the physical fitness of obese children aged 12 to 14 through school soccer training. Methods The effect of school soccer training on the health and physical fitness of obese children aged 12-14 years was studied, and conclusions were drawn by the literature method, experimental method, mathematical statistical method, and logical analysis method. Forty-eight screened obese children were randomly assigned to the experimental and control groups, 24 in each group. The experimental group underwent 12 weeks of soccer training, and the control group underwent 12 weeks of no training control. The subjects' body composition and flexibility quality indices were measured post-intervention. Results The visceral fat index, body fat rate, and muscle rate of boys and girls progressed expressively, with a significant difference (P <0.05). Muscle weight is also known as lean body weight, with an expressive increase in muscle tone. In comparison, the increase in fat weight and muscle ratio in boys was expressively higher than in girls. Conclusion Regular long-term school soccer training can increase mobility in obese children, increase physical flexibility, and help promote physical health and prevent injury. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

RESUMO Introdução Com base nos dados representativos que refletem o nível de desenvolvimento físico e qualidade atlética, como o "Teste Nacional de Saúde Física para Estudantes", é demonstrado que o estado de saúde física de adolescentes e crianças na China está diminuindo anualmente, e que a tendência de obesidade está aumentando gradualmente. Objetivo Analisar e estudar o efeito do treinamento na aptidão física de crianças obesas entre 12 a 14 anos de idade através do treinamento de futebol escolar. Métodos O efeito do treinamento de futebol escolar sobre a saúde e a aptidão física de crianças obesas de 12-14 anos de idade foi estudado, e as conclusões foram tiradas pelo método da bibliografia, método experimental, método estatístico matemático e método de análise lógica. Quarenta e oito crianças obesas submetidas a triagem foram designadas aleatoriamente aos grupos experimentais e de controle, 24 em cada grupo. O grupo experimental passou por 12 semanas de treinamento de futebol e o grupo de controle passou por 12 semanas sem controle de treinamento. A composição corporal e os índices de qualidade da flexibilidade dos sujeitos foram medidos antes e depois da intervenção. Resultados Resultados: O índice de gordura visceral, a taxa de gordura corporal e a taxa muscular de meninos e meninas progrediu expressivamente, com diferença significativa (P <0,05). O peso de musculatura também é conhecido como peso corporal magro, com um aumento expressivo do tônus muscular. Em comparação, o aumento do peso de gordura e da taxa muscular nos meninos foi expressivamente maior do que o encontrado nas meninas. Conclusão O treinamento regular de futebol escolar de longo prazo pode aumentar a mobilidade das crianças obesas, aumentar a flexibilidade física e ajudar a promover a saúde física além de prevenir lesões. Nível de evidência II; Estudos terapêuticos - investigação dos resultados do tratamento.

RESUMEN Introducción A partir de los datos representativos que reflejan el nivel de desarrollo físico y la calidad atlética, como la "Prueba Nacional de Salud Física para Estudiantes", se demuestra que el estado de salud física de los adolescentes y niños en China disminuye anualmente, y la tendencia de la obesidad aumenta gradualmente. Objetivo Analizar y estudiar el efecto del entrenamiento sobre la forma física de niños obesos de entre 12 y 14 años mediante el entrenamiento de fútbol escolar. Métodos Se estudió el efecto del entrenamiento de fútbol escolar en la salud y la forma física de niños obesos de 12 a 14 años, y se extrajeron conclusiones mediante el método bibliográfico, el método experimental, el método estadístico matemático y el método de análisis lógico. Cuarenta y ocho niños obesos examinados fueron asignados aleatoriamente a los grupos experimental y de control, 24 en cada grupo. El grupo experimental se sometió a 12 semanas de entrenamiento futbolístico y el grupo de control, a 12 semanas sin entrenamiento. Se midieron la composición corporal y los índices de calidad de la flexibilidad de los sujetos antes y después de la intervención. Resultados El índice de grasa visceral, el índice de grasa corporal y el índice muscular de niños y niñas progresaron expresivamente con diferencias significativas (P <0,05). El peso muscular también se conoce como peso corporal magro, con un aumento expresivo del tono muscular. En comparación, el aumento del peso graso y de la tasa muscular en los chicos fue expresivamente superior al observado en las chicas. Conclusión El entrenamiento regular de fútbol escolar a largo plazo puede aumentar la movilidad en niños obesos, incrementar la flexibilidad física y ayudar a promover la salud física, además de prevenir lesiones. Nivel de evidencia II; Estudios terapéuticos - investigación de los resultados del tratamiento.

[Observation Analyses of Aerosol Size Distribution Properties from February to March, 2019 in Tianjin Urban Area].

The aerosol size distribution is an important physical parameter reflecting the source, formation process, and pollution characteristics of aerosol particles. In order to study the properties of aerosol number concentration and size distributions in the Tianjin urban area,the aerosol number concentration and size distributions ranging from 10-600 nm were detected using a scanning mobility particle sizer (SMPS) during February and March, 2019. The results showed that in the Tianjin urban area, the aerosol number concentration,surface area concentration. and volume concentration in the size range of 10-600 nm were 22188.22 cm-3, 1581.08 µm2·cm-3, and 70.76 µm3·cm-3,respectively, in late winter and early spring. The aerosol number concentration,surface area concentration, and volume concentration spectrum were all unimodally distributed,and the peak value sizes were 109.40, 269.00, and 429.40 nm. The number concentrations of the nucleation mode (10-20 nm),Aitken mode (20-100 nm), and accumulation mode (100-600 nm) aerosols accounted for 1.40%, 52.44%, and 46.16% of the total number concentration. The diurnal variation in aerosol number concentration showed three peaks (06:00-08:00, 12:00-14:00, and 18:00-20:00) on work days and two peaks (07:00-08:00 and 19:00-21:00) on weekends. The peaks appeared 1-2 hours later on weekends,and the increment of aerosol number concentration was attributed to vehicle exhaust emissions. Meteorological factors had a significant influence on the aerosol size distribution in Tianjin; aerosol number concentration values were high in east and southwest wind. On non-precipitation days,the aerosol number size distribution moved to larger size ranges with the increment of relative humidity (RH); as the RH increased from <20% to 50%-60%,the size peak increased from 50 nm to 131 nm. The precipitation removed 100-200 nm aerosol particles discernibly,which resulted in the size peak decreasing to 98 nm.

[Characteristics of BTEX and Health Risk Assessment During Typical Pollution Episodes in Summer and Winter in Tianjin Urban Area].

Real-time BTEX(including benzene, toluene, ethylbenzene, m-, p-, and o-xylenes) were measured continuously in Tianjin urban site in July 2019 and January 2020 using a Syntech Spectras GC955 analyzer. The BTEX concentration levels, composition, and evolutionary mechanisms during typical pollution episodes were investigated. The potential sources of BTEX were analyzed qualitatively using the diagnostic ratios method. Finally, the BTEX health risk was evaluated by using the human exposure analysis and evaluation method according to US EPA. The averaged total mixing ratio of BTEX were 1.32×10-9 and 4.83×10-9 during ozone pollution and haze episodes, respectively. Benzene was the most abundant species, followed by toluene. The mixing ratio of BTEX was largely affected by short southwestern distance transportation in January, while local emissions in July. In addition, the BTEX mixing ratio depended on the influence of temperature and relative humidity(RH) in July, while the concentration was more sensitive to changes in RH when the temperature was low in January. Diagnostic ratios and source implications suggested that the BTEX was affected mainly by biomass/biofuel/coal burning during haze episodes. The traffic related emissions also had an impact except for the influence of biomass/biofuel/coal burning in July. The averaged hazard quotient(HQ) values were 0.072 and 0.29 during ozone pollution and haze episodes, respectively, which were in the upper safety range limit recommended by the US EPA. The carcinogenic risk posed by benzene in both cleaning and pollution processes was higher than the safety threshold set by the US EPA, which should be monitored carefully.

Evaluation and improvement study of the Planetary Boundary-Layer schemes during a high PM2.5 episode in a core city of BTH region, China.

Accurate depictions of planetary boundary layer (PBL) processes are important for both meteorological and air quality simulations. This study examines the sensitivity of the model performance of the Weather Research Forecasting model coupled with Chemistry (WRF-Chem) to five different PBL schemes and further to different turbulence parameters for the simulation of a winter haze episode in Tianjin, a core city of the Beijing-Tianjin-Hebei (BTH) region in China. To provide a direct and comprehensive evaluation of the PBL schemes, measurements from multiple instruments are employed, including both meteorological and air quality quantities from near-surface observations, vertical sounding measurements and ceilometer data. Moreover, the vertical distribution of the turbulent exchange coefficient is derived from sounding measurements and is utilized to evaluate the PBL schemes. The results suggest that the Mellor-Yamada-Janjic (MYJ) scheme is generally statistically superior to the other schemes when comparing observations. However, considerable model discrepancies still exist during certain stages of this haze episode, which are found to be predominantly due to the deficiency of MYJ in distinguishing the intensity of turbulent mixing between different pollution stages. To improve the model performance, this study further tests the impact of different closure parameters on the simulation of winter haze episode. In the MYJ scheme, the closure parameters play a key role in the turbulent mixing within the PBL and therefore in haze simulations. Sensitivity experiments with different MYJ parameters confirm this diagnosis and suggest that a larger Prandtl number (Pr), rather than the default value in the MYJ formulation, may be more applicable for haze simulations under stable atmospheric conditions.

Seasonal variation and secondary formation of size-segregated aerosol water-soluble inorganic ions in a coast megacity of North China Plain.

The aerosol samples of water-soluble inorganic ions (WSIs), including SO42-, NO3-, NH4+, Cl-, K+, Na+, Ca2+, and Mg2+ in size-segregated particulate matter (PM), were collected by an Anderson sampler (with 8 nominal cut-sizes ranged from 0.43 to 9.0 µm) in urban Tianjin during 2013-2014. The results showed that particulate matters in the fine mode (PM2.1, Dp < 2.1 µm) comprised large part of mass concentrations of aerosols, and the water-soluble ionic species in the fine mode were 47.07 ± 14.29 µg m-3 (spring), 67.87 ± 28.74 µg m-3 (summer), 86.60 ± 48.53 µg m-3 (autumn), and 104.16 ± 51.76 µg m-3 (winter), respectively, which accounted for 59.5%, 63.3%, 71.9%, and 71.4% of the PM2.1 mass concentrations. Secondary pollutants of SO42-, NO3-, and NH4+ (SNA) were the dominant contributors of WSIs, which showed a bimodal size distribution in each season, with the larger peak appeared in the size fraction of 0.65-1.1 µm and the smaller one in 3.3-5.8 µm fraction. SNA concentrations in lightly polluted days (LPD) and heavily polluted days (HPD) were observably higher than non-polluted days (NPD), especially in the fine mode, with the peak diameter moving from 0.43-0.65 µm on NPD to 0.65-1.1 µm on LPD and HPD. The correlation analysis between NH4+, NO3-, and SO42- suggested that almost all SO42- and NO3- for fine particles had been completely neutralized by NH4+, and primarily existed in the forms of (NH4)2SO4 and NH4NO3. The sulfur oxidation ratio (SOR) and nitrogen oxidation ratio (NOR) on LPD and HPD in fine mode were observably higher than those on NPD, especially in the range of 0.65-1.1 µm and 1.1-2.1 µm. Furthermore, SOR and NOR values in the size fraction of 0.43-3.3 µm increase as the RH elevated, especially in 0.43-2.1 µm, where RH was significantly positive correlated with SOR and NOR, indicating the significant contributions of heterogeneous processes to the secondary formation of SO42- and NO3-. These results suggested an enhanced formation ability of secondary pollutants under high RH in the coast city. Therefore, controlling the precursors of SNA, such as SO2 and NOx, would be more effective to reduce the fine particulate pollution in the coast megacity of Tianjin.

Comparison on aerosol physicochemical properties of sea and land along the coast of Bohai, China.

The Bohai Sea is one of four major sea areas adjacent to China, air pollution is becoming an issue along the Bohai coast owing to rapid industrialization and urbanization. To analyze the sea-land interaction and its influence on regional particulate pollution, a comparison of sea and land aerosol physicochemical properties was carried out using observations and numerical simulation. Three observation sites, an ocean site on the Bohai Sea, a coastal station in the Tanggu district, and an inland station in Tianjin City were established. The movements and interactions of pollutants between land and sea were determined, and it was found that the convergence of sea-land breezes produced an ascending motion, which served to concentrate pollutants, with the polluted central body of air extending upward to a height of 200 m. The proportion of fine particle aerosols was greater in Bohai than at the inland site, although aerosol pollution levels over land were higher than those over ocean. The annual average aerosol optical depths, at the Bohai and inland sites were 0.74 and 0.82, and the annual average wavelength indices were 0.97 and 0.90, respectively. The spatial distribution of PM2.5 concentration was characterized as inland > Bohai > coastal zone, which reflected local emissions, the special terrain and meteorological conditions of the coastal zone. Higher concentrations of EC, SO42-, Mg, Al, V, and Cr at Bohai, compared to the other sites, might have been due to ship emissions on the Bohai Sea, while industrial development could explain why the maximum concentrations of Fe and NO3- were observed at the coastal site. In addition, the diurnal distribution of SO42- exhibited a trend opposite to that for humidity, both at the Bohai and coastal sites, which indicated that, in addition to secondary transformation under high humidity conditions, sulfate emission sources were located locally.

[Transport Characteristics of PAN and O3 in the Lower Atmosphere of the Boundary Layer in Tianjin in Summer].

The volume concentration of peroxyacetyl nitrate (PAN) and O3 in the atmosphere were measured at the Tianjin Meteorological Tower in summer 2017 by using the online instrument with meteorological parameters and back trajectory analysis to analyze the delivery characteristics of PAN and O3. The average volume concentrations of PAN and O3 during the observational period are (0.73±0.56)×10-9 and (53±25)×10-9, respectively. The hourly maximum concentrations of PAN and O3 are 3.49×10-9 and 137×10-9. The volume concentrations of PAN and O3 show pronounced diurnal profiles, which are both characterized by much higher values at daytime than at nighttime. In addition, the correlation coefficient between PAN and O3 at daytime (R2=0.52) is notably higher than that at nighttime (R2=0.21). The air masses originating from the south show the highest volume concentration of PAN and O3, with the lowest volume concentration originating from the east. The wind rose plot and cluster analysis of the back trajectories show that the highest concentration of pollutants mainly originates in the southwest. The air massess originating from the east and circulating through the Bohai Sea and coastal areas of the Hebei and Liaoning provinces show the lowest volume concentrations of PAN and O3. The transportation within the boundary layer plays an important role in the concentration distribution of PAN and O3.

[Construction and Application of Vertical Diffusion Index for Analyzing Weather During Pollution Events in Tianjin].

Based on temperature and wind speed data from the 255 meter tall meteorological tower, the characteristics of atmospheric stability were analyzed in Tianjin, with the vertical diffusion index ß and φ constructed by atmospheric chemical models. This provided information to use the vertical dispersion analysis method to forecast pollution from weather data. The results show that the comprehensive use of atmospheric stability and the vertical diffusion index can provide a better pollution forecast. When the atmospheric stability was D from 07:00-08:00 and 18:00-20:00, compared to when atmospheric stability was C, the probability of heavy pollution weather increased by 10 times. If the vertical diffusion index ß and wind speed index were used to forecast heavy pollution, the accuracy rate was 67% higher than when using the single wind speed index. The coefficient between vertical diffusion index φ and PM2.5 mass concentration was 0.8.When the vertical diffusion index φ was less than 0.52, the probability of heavy pollution was 75%, identifying 59% of heavy pollution events.

Vertical observation and analysis on rapid formation and evolutionary mechanisms of a prolonged haze episode over central-eastern China.

To clarify the rapid formation and evolutionary mechanisms of an extremely severe and persistent haze and fog (HF) episode that occurred in central-eastern China from Dec 20 to 25, 2015, a novel campaign was conducted and vertical profiles of wind, temperature, light extinction coefficient (LEC) and PM2.5 concentration were used to analyze the rapid formation and evolutionary mechanisms of this HF episode. The substantial downward transportation of regional pollution from high layers and stagnant weather conditions favorable for the local pollution accumulation were the two main causes of the rapid increase in pollutant concentration. Southwest wind speeds of 4m/s between 300 and 600m and obvious downward flows were observed, whereas the southwest wind speeds were low below 300m, and strong temperature inversion with intensity of 4.5°C/100m expanded vertically to a height of 600m. Two peaks of PM2.5 concentration were observed at 200 and 700m, corresponding to 235 and 215µg/m3, respectively. The frequent change in wind direction and wind speeds resulted in the fluctuation of PM2.5 concentration. The turbulence within lower layers of the troposphere was enhanced by easterly and northerly winds which decreased the pollution level; however, the strength and stretching height of the winds were insufficient to fully clear the air of pollutants. The PM2.5 concentration revealed 2-high concentration layers in the vertical direction. The maximum concentration layer was below 100m, while the second high-concentration layer was at 400m.

[Characteristics of the Size Distribution of Water-soluble Ions During a Heavy Pollution Episode in the Winter in Tianjin].

To characterize the size distribution of water-soluble inorganic ions (WSⅡ) during a heavy pollution episode, particle samples were collected by an Andersen cascade sampler in Tianjin in January 2014, and the concentrations of eight WSⅡ (Na+, NH4+, K+, Mg2+, Ca2+, Cl-, NO3-, and SO42-) during a typical haze episode were analyzed by ion chromatography. The sources and formation mechanisms of WSⅡ were analyzed based on their size distributions. The results showed that the daily average concentrations of PM2.5 and PM10 were (138±100) µg·m-3 and (227±142) µg·m-3, respectively, and the average concentration of total WSⅡ concentrations (TWSⅡ) in the coarse and fine particles were (34.07+6.16) µg·m-3 and (104.16+51.76) µg·m-3, respectively. The concentrations of SO42-, NO3-, and NH4+ in the fine particles were much higher than concentrations of the other ions, and there were strong correlations between these three ions. The TWSⅡ on clear days, light pollution days, and heavy pollution days were (41.55±12.41) µg·m-3, (94.46±31.19) µg·m-3, and (147.55±27.76) µg·m-3, respectively. On clear days, SO42- showed a unimodal distribution, peaking at 0.43-0.65 µm; and NO3- showed a trimodal distribution, peaking at 0.43-0.65 µm, 2.1-3.3 µm, and 5.8-9.0 µm. NH4+ had a bimodal distribution, peaking at 0.43-0.65 µm and 4.7-5.8 µm. On heavy pollution days, however, the size distributions of these three secondary inorganic ions switched to a unimodal size distribution, peaking at 0.65-1.1 µm. Unimodal NH4+ mainly coexisted with SO42- and NO3-, and the excess NH4+ was found to be combined with Cl- in the fine particles. In the coarse particles, NH4+ completely coexisted with SO42- and NO3-.

Vertical characteristics of PM2.5 during the heating season in Tianjin, China.

In this study, PM2.5 samples were collected at four heights (10m, 40m, 120m and 220m) at a meteorological tower in the daytime and nighttime during the heating season in Tianjin, China. The vertical variation and diurnal variability of the concentrations of PM2.5 and main chemical compositions were analyzed in clear days and heavy pollution days. Generally, mass concentrations of PM2.5 and the chemical compositions showed a decreasing trend with increasing height, while mass percentages of SO4(2-), NO3(-) and OC showed an increasing trend with increasing height. Concentrations of ion species and carbon compound in PM2.5 samples in the daytime were higher than those collected at night, which was due to intense human activities and suitable meteorological condition in the daytime. The ratios of NO3(-)/SO4(2-) and OC/EC were also considered, and we have observed that their levels on heavy pollution days were higher than those on clear days. In addition, source apportionments were identified quantitatively using the CMB-iteration model. The results indicated that contributions of secondary ion species increased with increasing height, while contributions of other pollutant sources decreased, and contributions of vehicle exhaust were relatively high on clear days.

"All air-plasma" terahertz spectroscopy.

We demonstrate terahertz wave generation and detection capabilities up to 6 THz without the need for solid state materials, biased electrodes, or forward propagating signal collection. An "all air-plasma" terahertz system is used to encode explosive material resonant signatures into the 357 nm nitrogen fluorescence line of a bichromatic field-induced laser plasma filament. These results show the practicability to extend these measurements to remote locations where terahertz pulse information is no longer limited by water vapor absorption, phonon resonance, or signal collection directionality.

Laser-induced photoacoustics influenced by single-cycle terahertz radiation.

Laser-induced plasma acoustic waves are enhanced under the illumination of single-cycle terahertz (THz) radiation, making THz-enhanced acoustics (TEA) a useful method for THz wave detection. During a single-cycle THz pulse with its peak field of 100 kV/cm, a pressure enhancement of 10% is observed throughout the acoustic spectrum up to 140 kHz, and the TEA signal is found to increase linearly with THz wave intensity. By using dual-color laser excitation to manipulate free electron drift, it is possible to modulate the enhanced acoustic signal and recover a coherent THz time-domain waveform by simply "listening" to the plasma.

Enhancement of photoacoustic emission through terahertz-field-driven electron motions.

We report the study of enhanced photoacoustic emission from a laser-induced plasma under the influence of the terahertz field up to 100 kV/cm. We theoretically and experimentally investigate the energy transfer from terahertz radiation to molecular translational motion, through terahertz-field-driven electron motion and inelastic electron-molecule collision. The enhanced photoacoustic emission in the frequency range of 1-140 kHz is quadratically dependent on the incident terahertz field. We also demonstrate, as an application, that the enhancement of photoacoustic emission from gases asymmetrically ionized by two-color laser field can be used for coherent terahertz wave detection.

Terahertz-radiation-enhanced emission of fluorescence from gas plasma.

We report the study of femtosecond laser-induced air plasma fluorescence under the illumination of terahertz (THz) pulses. Semiclassical modeling and experimental verification indicate that time-resolved THz radiation-enhanced emission of fluorescence is dominated by the electron kinetics and the electron-impact excitation of gas molecules or ions. We demonstrate that the temporal waveform of the THz field could be retrieved from the transient enhanced fluorescence, making omnidirectional, coherent detection available for THz time-domain spectroscopy.