Three-dimensional augmentation for hyperspectral image data of water quality: An Integrated approach using machine learning and numerical models.

This research introduces a comprehensive methodology to enhance hyperspectral image data (HSD) utility, specifically focusing on the three-dimensional (3-D) augmentation of Chlorophyll-a (Chl-a). This study comprises three significant steps: (1) the augmentation of limited field water quality data in terms of time interval and number of variables using neural network models, (2) the generation of 3-D data using numerical models, and (3) the extension of the hyperspectral image data into 3-D data using machine learning models. In the first phase, Multilayer Perceptron (MLP) models were developed to train water quality interactions and successfully generated high-frequency water quality data by adjusting biased measurements and predicting detailed water quality variables. In the second phase, high-frequency data generated by MLP models were applied to develop two numerical models. These numerical models successfully generated 3-D data, thereby demonstrating the effectiveness of integrating numerical modeling with neural networks. In the final phase, ten machine learning models were trained to generate 3-D Chl-a data from HSD. Notably, the Gaussian Process Regression model exhibited superior performance, effectively estimating 3-D Chl-a data with robust accuracy, as evidenced by an R-square value of 0.99. The findings align with theories of algal bloom dynamics, further validating the effectiveness of the approach. This study demonstrated the successful integrated development for HSD extension using machine learning models, numerical models, and original HSD, highlighting the potential of such integrated methodologies in advancing water quality monitoring and estimation. Notably, the approach leverages readily accessible data, allowing for the swift generation of results and bypassing time-consuming data collection processes. This research marks a significant step towards more robust, comprehensive water quality monitoring and prediction, thereby facilitating better management of aquatic ecosystems.

Improving Cardiorespiratory and Muscular Function of Korean Firefighters: A Kinect-Based Mixed Reality Device Exercise Intervention Randomized Control Trial.

OBJECTIVE: This study addresses declining physical fitness among Korean firefighters due to a low exercise participation rate caused by the absence of exercise instructors. The research explores Virtual Mate (VM), a Kinect-based mixed reality device, as a potential solution, but its capacity to replace training instructors in enhancing physical fitness remains uncertain. METHODS: Twenty Korean male firefighters were divided into two groups: the exercise group received an 8-week intervention using VM, while the control group maintained regular physical activity. Cardiopulmonary function and muscle function were measured. RESULTS: After 8 weeks, the exercise group demonstrated a significant improvement in VO 2peak . Furthermore, there were notable enhancements in the strength and endurance of most knee, shoulder, and trunk flexors and extensors. CONCLUSIONS: Integrating VM into an exercise program can effectively improve cardiorespiratory and muscular function in Korean firefighters.

Identification of pollutant sources and evaluation of water quality improvement alternatives of a large river.

While pollutants are the most important factors for the deterioration of surface water quality, the identification of major pollutant sources for rivers is challenging, especially in areas with diverse land covers and multiple pollutant inputs. This study aims to identify the significant pollutant sources from the tributaries that are affecting the water quality and identify the limiting nutrient for algal growth in the Geum river to provide a management alternative for an improvement of the water quality. The positive matrix factorization (PMF) was applied for pollutant source identification and apportionment of the two major tributaries, Gab-cheon and Miho-cheon. Positive matrix factorization identifies three and two major pollutant sources for Gab-cheon and Miho-cheon, respectively. For Gab-cheon, wastewater treatment plants, urban, and agricultural pollution are identified as major pollutant sources. Furthermore, for Miho-cheon, agricultural and urban pollution were identified as major pollutant sources. Total phosphorus (TP) is also identified as a limiting nutrient for algal growth in the Geum river. Water quality control scenarios were formulated and improvement of water quality in the river locations was simulated and analyzed with the Environmental Fluid Dynamic Code (EFDC). Scenario results were evaluated using a water quality index. The reduction of total phosphorus (TP) from the tributaries has greatly improved the water quality, especially algal bloom in the downstream stations.

Changes in Physical Fitness among Elementary and Middle School Students in Korea before and after COVID-19.

The present study aimed to analyze changes in health-related physical fitness among Korean elementary and middle school students before (2019) and after (2021) the COVID-19 pandemic. Data collection was completed by requesting the physical activity promotion system (PAPS) data from elementary and middle school students. This information is obtained annually by the Goyang Office of Education in Gyeonggi-do, Korea. The collected data were measured in 2019 and 2021. Data were collected from 17,000 children in the fifth and sixth grades of elementary school and about 24,000 boys and girls in the first, second, and third grades of middle school. Chi-square analyses were used to examine data from each school's health-related physical fitness examinations. Our results indicated that physical fitness levels were significantly lower in 2021 than in 2019 across the following six areas: cardiorespiratory endurance, power, muscular strength, flexibility, obesity, and overall health-related physical fitness (p < 0.05). In addition, the ratio of students with excellent physical fitness (PAPS Grades 1 and 2) significantly decreased from 2019 to 2021, while the ratio of students with poor physical fitness (PAPS Grades 3, 4, and 5) increased (p < 0.05). In addition, there were some differences according to grade and gender. Discussions regarding the impact of decreases in physical activity on physical fitness, interpretations of physical fitness in the context of a pandemic, and practical measures that can be implemented to improve health and fitness among children and adolescents in such situations remain essential.

Differences in salient beliefs associated with voluntary exercise training among South Korean firefighters before and after COVID-19.

BACKGROUND: Participating in voluntary exercise training is important to meet occupational requirements as well as firefighters' health and safety. The purpose of this study is to identify salient beliefs associated with voluntary exercise training among firefighters in the pandemic era by comparing outcomes with those from a previous elicitation study, which was carried out before the COVID-19 outbreak. METHODS: A total of 57 firefighters are recruited to participate in an elicitation study. Participants are requested to respond to six open-ended questions related to voluntary exercise training. Content analysis is used to create categories that combine similar factors in each belief. Beliefs mentioned by more than 30% of participants are used for comparison with the results of the previous research. RESULTS: "Improves my physical ability" (n = 44) and "cause injury" (n = 17) are identified as behavioral beliefs in the present study, whereas "makes me tired" and "takes too much time" were also elicited in Lee's study. Normative beliefs are "family members" (n = 45) and "colleagues" (n = 27) and these results are consistent with those in Lee's study. "Lack of time" (n = 28), "exercise facilities" (n = 19), and "COVID-19" (n = 19) are elicited as control beliefs in the present study, whereas "physical condition" (n = 21) and "exercise partners" (n = 14) were elicited as other control beliefs, and "COVID-19" was not mentioned in Lee's study. CONCLUSION: This study can contribute valuable information about salient beliefs associated with exercise training behavior among firefighters, particularly under pandemic conditions. Future researchers should develop tailored exercise training programs for firefighters based on current elicited beliefs.

Process and Outcome Evaluations of Interventions to Promote Voluntary Exercise Training Among South Korean Firefighters.

The main aim of the present study is to evaluate reach, dose, fidelity, and outcomes of the interventions for promoting voluntary exercise training among South Korean firefighters. Four interventions for promoting voluntary exercise training among firefighters (i.e., virtual reality exercise system intervention, poster intervention, monitor intervention, and wearable health device intervention) were performed in a fire station located in Seoul, South Korea. To evaluate reach and dose received related to each intervention, participants were asked to answer several simple questions. Three process evaluators completed a 20-item survey to share their impressions related to the quality of intervention delivery. Paired t test was used to examine mean changes in primary (i.e., mean minutes of exercise training per week) and secondary outcomes (i.e., beliefs and intention) between pre- and postinterventions. More than 60% of participants experienced monitor and wearable health device interventions. Process evaluators tend not to agree with a statement saying that the number of the virtual reality exercise equipment was appropriate. Among firefighters who participated in exercise training less than 150 min per week at 1-month follow-up, mean minutes of exercise training per week increased by 67.95 min after interventions. Future studies need to examine whether the monitor and wearable health device interventions effectively increase exercise training participation among firefighters in other fire stations located in Seoul, South Korea.

Localized Corrosion Resistance on Additively Manufactured Ti Alloys by Means of Electrochemical Critical Localized Corrosion Potential in Biomedical Solution Environments.

This study proposes a new method, electrochemical critical localized corrosion potential (E-CLCP), in order to evaluate localized corrosion resistance of biomedical additive manufacturing (AM) titanium (Ti) alloys. The procedures for determining E-CLCP are completely different from that of the electrochemical critically localized corrosion temperature (E-CLCT) method (ISO 22910:2020). However, its application should be limited to pH and temperature of the human body because of the temperature scan. E-CLCP displays the localized corrosion resistance of AM Ti alloys based on the human body's repassivation kinetics, whereas E-CLCT displays the localized corrosion resistance of the alloys based on passive film breakdown in much harsher corrosive environments.

The Effects of Number of Fire Dispatches and Other Situational Factors on Voluntary Exercise Training Among Korean Firefighters: A Multilevel Logistic Regression Analysis.

According to previous research, participation in exercise training (ET) by South Korean firefighters varies with shift type, and the effect of shift type is greater in large cities than in small towns. However, shift types differ among regions, depending on the number of dispatches. Therefore, the present study examined the impact of the number of fire dispatches and other situational factors on ET. A series of multilevel logistic regression analysis was applied to analyze the data collected from South Korean firefighters (N = 5219) in 2017. According to the firefighters, participation in ET is higher among those who have someone to instruct their ET (Coefficient (Coef) = 0.057, SE = 0.017, p < 0.001) and who can do ET while on duty (Coef = 0.048, SE = 0.014, p < 0.001). The number of fire dispatches had a significant effect on participation in ET (Coef = -0.000, SE = 0.000, p < 0.01), meaning that the firefighters' participation in ET varies with the number of fire dispatches in each region. Our main findings indicate that the number of fire dispatches is a key factor affecting ET participation among firefighters, and the other situational factors also play a role. Therefore, ET programs that firefighters can participate in between calls should be established.

Predicting Voluntary Exercise Training among Korean Firefighters: Using Elicitation Study and the Theory of Planned Behavior.

Background: Firefighters are required to have high levels of aerobic and anaerobic power because they often perform physically demanding work in dangerous environments. Therefore, it is important to find out salient factors influencing voluntary exercise training among Korean firefighters based on well-validated theory. Methods: The present study conducted an elicitation study to elicit salient behavioral, normative, and control beliefs about exercise training among Korean firefighters and identified salient beliefs that have a significant indirect effect on behavior through intention using structural equation modeling. Results: Although ten modal salient beliefs obtained from our elicitation study are similar to those elicited from previous TPB belief-based research with a focus on exercise behavior, only three of these (i.e., "improves my physical ability" (coef. = 0.078, p = 0.006), "takes too much time" (coef. = 0.064, p = 0.023), and "colleagues" (coef. = 0.069, p = 0.016) indirectly influenced exercise training behavior through intention among Korean firefighters. Conclusions: Our results may contribute to the literature by providing important information suggesting that three modal salient beliefs are major cognitive determinants of exercise training behavior among Korean firefighters and they may play an essential role in developing effective programs or policies for promoting Korean firefighters' exercise training.

Relationship between Shift Type and Voluntary Exercise Training in South Korean Firefighters.

BACKGROUND: According to the National Fire Agency, 69% of South Korean firefighters prefer the three circuit system. Since the three circuit system involves working for 24 h consecutively, it could reduce work performance of firefighters and their participation in exercise training (ET) and fitness levels could be affected by shift type. The present study examined the impact of shift type on ET and identified the interaction effect between shift type and city size on ET among South Korean firefighters. METHODS: A series of logistic regression models were used to analyze the data collected from incumbent outside workers among Korean firefighters (N = 5196) in 2017. RESULTS: Firefighters under the 3 circuit system participated in ET less frequently than did those under the 21 circuit system, and the difference was greater in large cities than in small towns. This could be because of the greater opportunity to participate in leisure activities in large cities, or because participating in ET is easier for firefighters in small towns, who tend to be less busy than those in large cities. CONCLUSIONS: The three circuit system is not feasible in the present situation in South Korea. Therefore, an environment suitable for the three circuit system should be established.

Echocardiography Evaluation of Left Ventricular Diastolic Function in Elderly Women with Metabolic Syndrome.

To date, we found no published reports on the effects of metabolic syndrome and physical activity levels on left ventricular (LV) diastolic function in elderly women aged over 65 years. Our study involved patients with echocardiographically normal LV ejection fractions (≥50%) and normal LV dilatation diameters (≤55 mm). Elderly women with metabolic syndrome (n = 20) and healthy elderly women (n = 17) were selected and assessed with the National Cholesterol Education Program Adult Treatment Panel III, a metabolic syndrome diagnostic instrument. We compared the LV function indices and physical activity levels according to the presence (metabolic syndrome group) or absence (normal group) of metabolic syndrome. The LV end-systolic (LVES) diameter was significantly smaller (p = 0.037) and LV outflow tract (LVOT) diameter was significantly larger (p = 0.030) in the metabolic syndrome group. The left arterial dimension at end-systole (p = 0.024), left arterial volume (LAV) index (p = 0.015), early peak mitral inflow velocity (E, p = 0.031), early diastolic mitral annulus motion velocity (E'-septal, p = 0.044), (E'-lateral, p = 0.008), and E/late peak mitral inflow velocity ratio (E/A, p = 0.006) values were significantly lower and physical activity levels (p = 0.034) were significantly higher in the metabolic syndrome group. These results indicated that the metabolic syndrome group had relatively high physical activity levels compared to the normal group, which may have positively affected the LVES, LVOT, left atrial volume index, E, E', and E/A values.

Educating restaurant owners and cooks to lower their own sodium intake is a potential strategy for reducing the sodium contents of restaurant foods: a small-scale pilot study in South Korea.

BACKGROUND/OBJECTIVES: This study was conducted to evaluate the feasibility of a sodium reduction program at local restaurants through nutrition education and examination of the health of restaurant owners and cooks. SUBJECTS/METHODS: The study was a single-arm pilot intervention using a pre-post design in one business district with densely populated restaurants in Seoul, South Korea. The intervention focused on improving nutrition behaviors and psychosocial factors through education, health examination, and counseling of restaurant personnel. Forty-eight restaurant owners and cooks completed the baseline survey and participated in the intervention. Forty participants completed the post-intervention survey. RESULTS: The overweight and obesity prevalences were 25.6% and 39.5%, respectively, and 74.4% of participants had elevated blood pressure. After health examination, counseling, and nutrition education, several nutrition behaviors related to sodium intake showed improvement. In addition, those who consumed less salt in their baseline diet (measured with urine dipsticks) were more likely to agree that providing healthy foods to their customers is necessary. This study demonstrated the potential to reduce the sodium contents of restaurant foods by improving restaurant owners' and cooks' psychological factors and their own health behaviors. CONCLUSIONS: This small pilot study demonstrated that working with restaurant owners and cooks to improve their own health and sodium intake may have an effect on participation in restaurant-based sodium reduction initiatives. Future intervention studies with a larger sample size and comparison group can focus on improving the health and perceptions of restaurant personnel in order to increase the feasibility and efficacy of restaurant-based sodium reduction programs and policies.

Analysis of physical fitness and technical skills of youth soccer players according to playing position.

The purpose of this study was to compare performance factors of youth soccer players according to position. A total of 101 high school soccer players were selected and were classified into goalkeeper (n=7), defense (n=37), midfield (n=39), and forward (n=18) positions. All subjects were subjected to the Wingate test for anaerobic capacity, shuttle run test for aerobic capacity, and pass, kick, dribble, and shooting tests for soccer skills. There was no significant difference in aerobic capacity according to position. However, anaerobic capacity was significantly higher in defenders than midfielders (P<0.05), and soccer skills were significant lower in goalies than in other positions (P<0.01). The results show significant differences in anaerobic capacity and soccer skills according to position in youth soccer players. Therefore, we suggest that middle and high school soccer players should improve aerobic, an-aerobic capacity, and soccer skills irrespective position to achieve high-level soccer performance.

Comparative Effects of Vigorous-Intensity and Low-Intensity Blood Flow Restricted Cycle Training and Detraining on Muscle Mass, Strength, and Aerobic Capacity.

Traditional high-intensity aerobic training has been shown to improve muscle protein synthesis and aerobic capacity; however, recent research indicates that low-intensity aerobic training with blood flow restriction (BFR) may have similar effects. The purpose of this study was to compare the effects of vigorous-intensity (VI) cycling vs. low-intensity cycling with BFR (LI-BFR) on muscle mass, strength, and aerobic capacity after training and subsequent detraining. Thirty-one physically active subjects were assigned to one of 3 groups: VI (n = 10, 60-70% heart rate reserve [HRR]), LI-BFR (n = 11, 30% HRR with BFR at 160-180 mm Hg), and no exercise control (n = 10, no exercise). Subjects in VI and LI-BFR cycled 3 times per week for 6 weeks (total 18 sessions). Body composition, muscle mass, strength, and aerobic capacity were measured pre, post, and after 3 weeks of detraining. A group × time interaction (p = 0.019) effect for both knee flexion and leg lean mass was found. For both VI and LI-BFR groups, knee flexion strength was significantly increased between pre and post (p = 0.024, p = 0.01) and between pre and 3 week-post (p = 0.039, p = 0.003), respectively. For the LI-BFR group, leg lean mass was significantly increased between pre and 3 week-post (p = 0.024) and between post and 3 week-post (p = 0.013). However, there were no significant differences between groups for any variables. The LI-BFR elicits an increase in the knee flexion muscle strength over time similar to the VI. An increase in the leg lean mass over time was seen in the LI-BFR, but not in VI and CON.

Differences in Perceived Health Status Outcomes among Heterosexual, Homosexual (Gay or Lesbian) and Bisexual Korean adolescents / Diferencias en el estatus de salud percibido entre adolescentes coreanos heterosexuales, homosexuales (gays o lesbianas) y bisexuales

The purpose of this study was to examine differences in perceived health status outcomes among heterosexual, homosexual (gay or lesbian), and bisexual Korean adolescents. Originally, in 2012, over 70,000 adolescents aged 12-18 years participated in the Eighth Korea Youth Risk Behavior Web-based Survey (KYRBWS -VIII). However, only 11,829 adolescents provided information on their sexual experiences and behaviors, such as kissing, fondling, and sexual orientations, i.e., homosexual (gay or lesbian), bisexual, or heterosexual. Therefore, data from only 11,829 adolescents surveyed were analyzed using a one -way analysis of variance, with a Scheffe post-hoc test, to determine the differences in perceived health status outcomes among Korean adolescents of the different sexual orientation groups. Boys across all 3 groups showed significant differences in general health status (p = 0.004), happiness (p = 0.045), and getting sufficient sleep (p = 0.004). Further, Scheffe post-hoc comparisons of group mean scores revealed that homosexual (gay) boys had poorer overall health (p = 0.004) and bisexual boys had less sufficient sleep (p = 0.017); however, there were no significant differences in happiness between homosexual (gay) (p = 0.651) and bisexual boys (p = 0.064) as compared to heterosexual boys. Moreover, there were no significant differences in general body shape (p = 0.320) and oral health (p = 0.549) among the 3 groups we studied. Girls differed significantly in general body shape (p = 0.026) across all 3 groups in the results of the one-way ANOVA we performed. However, according to Scheffe post-hoc analyses, no significant differences existed in general body shape among girls in both the homosexual (lesbian) and bisexual groups (p = 0.112 and 0.204, respectively). Additionally, there were no significant differences in general health status (p = 0.113), happiness (p = 0.602), oral health (p = 0.290), and getting sufficient sleep (p = 0.481) among adolescent girls in all 3 groups. From these results, we concluded that, in general, homosexual (gay or lesbian) and bisexual Korean teens do not differ significantly from heterosexual Korean teens in perceived health status outcomes.

El propósito de este estudio fue examinar las diferencias en los resultados del estado de salud percibido entre adolescentes coreanos heterosexuales, homosexuales (gays o lesbianas) y bisexuales. Originalmente, en 2012, más de 70.000 adolescentes de 12 a 18 años participaron en la Octava Encuesta Coreana para la Juventud sobre comportamientos riesgosos (KYRBWS-VIII). Sin embargo, sólo 11.829 adolescentes proporcionaron información sobre sus experiencias sexuales y comportamientos, como los besos, las caricias, y orientaciones sexuales, es decir, homosexual (gay o lesbiana), bisexual o heterosexual. Por lo tanto, los datos de sólo 11.829 adolescentes encuestados fueron analizados mediante un análisis de varianza, con una prueba post-hoc de Scheffe, para determinar las diferencias en los resultados del estado de salud percibido entre los adolescentes coreanos de los diferentes grupos de orientación sexual. Jóvenes en todos los 3 grupos mostraron diferencias significativas en el estado de salud general (p = 0,004), la felicidad (p = 0,045), y dormir lo suficiente (p = 0,004). Además, las comparaciones de grupo post-hoc de Scheffe muestran las puntuaciones significativas que revelan que los homosexuales (gay) chicos tenían peor salud general (p = 0,004) y los chicos bisexuales presentaban una deficiencia en el sueño (p = 0,017); sin embargo, no hubo diferencias significativas en la felicidad entre homosexual (Gay) (p = 0,651) y chicos bisexuales (p = 0,064) en comparación con los niños heterosexuales. Por otra parte, no hubo diferencias significativas en la forma general del cuerpo (p = 0,320) y la salud oral (p = 0,549) entre los 3 grupos estudiados. Las niñas difieren significativamente en la forma del cuerpo general (p = 0,026) en todos los 3 grupos en los resultados de la ANOVA de una vía. Sin embargo, de acuerdo con el análisis post-hoc de Scheffe, no existen diferencias significativas en forma general del cuerpo de las niñas, tanto en el homosexual (lesbiana) y bisexuales (p = 0,112 y 0,204, respectivamente). Además, no hubo diferencias significativas en el estado de salud general (p = 0,113), la felicidad (p = 0,602), la salud oral (p = 0,290), y dormir lo suficiente (p = 0,481) entre las adolescentes en los 3 grupos. A partir de estos resultados, se concluye que, en general, los adolescentes homosexuales (gays o lesbianas) y bisexuales de Corea no difieren significativamente de los adolescentes coreanos heterosexuales en los resultados del estado de salud percibido.

Sleep duration and school performance in Korean adolescents / Duración del sueño y desempeño escolar en adolescentes coreanos

Background This study investigated the relationship between sleep duration and school performance in Korean adolescents. Methods In 2012, 63 688 adolescents participated in the 8th Korea Youth Risk Behavior Web-Based Survey (KYRBWS-VIII) project. The relationship between sleep duration and school performance was evaluated by multivariate logistic regression analysis after adjustment for covariate variables, including body mass index, age, parental education, economic status, mental stress, smoking, alcohol consumption, breakfast patterns, and three measures of physical activity. Results For boys, but not for girls, 5-6 hours of sleep/night were related to average or better academic performance (OR: 1.094, 95% CI [1.011-1.182], p=0.025) compared to ≤4 hours/night. For both boys and girls, nine or more hours/night were negatively related to academic performance (boys: 0.657, [0.554-0.779; p<0.001]; girls: ≥9 hours/night, 0.664 [0.572-0.771], p<0.001) compared to ≤4 hours/night. Conclusion Whilst it may appear that five to six hours of sleep are necessary to maintain average or better than average school performance for boys, nine or more hours are detrimental to school performance for both groups. This study was limited by the following factors: data were collected only for weekdays and it is. Other sleep variables, such as quality of sleep and sleepiness, should be investigated for a further understanding of these results.

Antecedentes En este estudio se investigó la relación entre la duración del sueño y el desempeño escolar en adolescentes coreanos. Métodos En 2012, 63 688 adolescentes participaron en el octavo proyecto de Estudio de Conducta de Riesgo Juvenil Basado en la Red (KYRBWS-VIII, por sus siglas en inglés). La relación entre la duración del sueño y el desempeño escolar se evaluó mediante un análisis de regresión logística multivariada tras ajustar para las variables covariadas, incluyendo índice de masa corporal, edad, nivel educativo de los padres, posición económica, estrés mental, consumo de tabaco, consumo de alcohol, patrones en el desayuno y tres mediciones de actividad física. Resultados En el caso de los chicos, pero no así en el de las chicas, de cinco a seis horas de sueño por noche se relacionaron con un desempeño académico promedio o mejor que el promedio (R.M.: 1.094, 95% CI [1.011-1.182], p=0.025) en comparación con ≤ cuatro horas/ noche. Tanto para los chicos como para las chicas, nueve o más horas/noche se relacionaron de forma negativa con el desempeño académico (chicos: 0.657 [0.554-0.779; p<0.001]; chicas ≥9 horas/noche, 0.664 [0.572-0.771], p<0.001) en comparación con ≤4 horas/noche. Conclusión Para los chicos, de cinco a seis horas de sueño son necesarias para mantener un desempeño escolar promedio o mejor que el promedio, en tanto que nueve o más horas son perjudiciales para el desempeño escolar de tanto los chicos como las chicas. Otras variables del sueño, como la calidad del sueño y la somnolencia, deben investigarse para obtener una mejor comprensión de estos resultados.

Occurrence of micropollutants in four major rivers in Korea.

There has been an increasing concern in recent years over the presence of numerous micropollutants in river water. Simultaneously, risk assessment of micropollutants has become increasingly important due to their high toxicity. Therefore, the aims of this study were to characterize the levels of micropollutants in rivers, to identify the sources of these pollutants, and to evaluate their risk quotients (RQ) to the ecological system. Monitoring data from 159 sites distributed across four major rivers in Korea were collected from the Ministry of the Environment (KME) reports. Tests were performed to check for the presence of 35 pollutants in river waters, from which 29 pollutants were detected. Organochlorine pesticides (OCPs) occurred most frequently, at low concentrations, whereas volatile organic compounds (VOCs) and phthalates were detected at higher concentrations. Based on this study, it was suggested that the factories near the sampling sites where pollutants were found represent one of the main sources of chemicals. After comparing the industrial activities with the measured pollutants, although the released amounts were not reported, representative intermediate chemicals were found in the river water. The RQs of most VOCs were below one, despite their concentration range being higher, compared with other pollutants. Methyl bromide and di-n-octyl phthalate occurred frequently in the Han River Basin and the Nakdong River Basin, respectively, and their RQs were consistently high, so further studies should focus on their exact emission source in order to reduce ecological risk. The results suggest that it will be necessary to develop methods of risk assessment that are more tailored to the various micropollutants present in river water, in addition to the implementation of water treatment systems to reduce ecological risk.

Jump test performance and sarcopenia status in men and women, 55 to 75 years of age.

BACKGROUND AND PURPOSE: Jumping mechanography uses maximal countermovement jumps to test obtain such as jump power (JPow). Recently, it has been shown to be a safe method for assessing muscle function in older adults; however, little is known about the relationships between JPow, muscle strength, and sarcopenia status. The purpose of this study was to examine jump performance, muscle strength, and sarcopenia status in older adults. METHODS: This was a cross-sectional study that included men (n = 27) and women (n = 33) (55-75 years) recruited from the general community. Participants completed health status and physical activity questionnaires. Body composition, including appendicular skeletal muscle mass (ASM), bone free lean body mass, and relative skeletal muscle mass index, were assessed by total body dual-energy x-ray absorptiometry scans. The criteria for sarcopenia were relative skeletal muscle mass index values less than 7.26 kg/m2 for men and less than 5.45 kg/m2 for women. Three vertical jumps on a jump mat were performed to assess JPow, jump velocity (JVel), and jump height (JHt). Muscle strength was measured by 1RM testing for leg press (LP) and right and left hip abduction isotonic resistance exercises. RESULTS: Sarcopenia was found in 20% (12/60) of the participants. Jump power was significantly lower (P = .001) in the sarcopenia group than in the normal group, 651.1 (41.7) W versus 851.0 (27.4) W, respectively. Jump power and JHt were significantly (P < .01) positively correlated (r = 0.54-0.77) with ASM and bone free lean body mass. Significant (P < .01) positive correlations (r = 0.43-0.70) were also reported between jump test variables (JPow, JVel, JHt) and muscle strength (LP, right and left hip abduction). DISCUSSION: The jump test protocol was conducted safely with no injuries or balance issues. Our finding of lower JPow in sarcopenic individuals adds new information to the existing literature on age-related declines in muscle power. CONCLUSION: Community-dwelling individuals classified as sarcopenic had significantly lower JPow but not muscle strength compared with their counterparts with normal amounts of muscle mass. Jump test variables were positively correlated with lean tissue and lower body muscle strength. Based on our findings, JPow may be useful for sarcopenia screening in the middle-aged and older adults; however, more research is needed to determine the utility of this method in clinical populations.

Association between obesity and various parameters of physical fitness in Korean students.

The purpose of this study was to evaluate the association between the types of obesity classified according to the body mass index (BMI) and/or waist circumference (WC) and the various parameters of physical fitness in Korean college students. BMI, WC, and fitness assessments were performed on 726 male college student volunteers who visited a public health center in Seoul, Korea. Classification based on BMI and/or WC was established according to the data in the WHO's Asia-Pacific standard report, and the subjects were divided into the following 4 groups: (1) obese as determined by BMI, but not WC (BMI Obesity Group, BOG); (2) obese as determined by WC, but not BMI (WC Obesity Group, WOG); (3) obese as determined by both BMI and WC (BWOG); and (4) non-obese normal group (NG). Fitness assessment parameters such as cardiorespiratory endurance, cardiovascular function, muscular endurance, muscular strength, flexibility, power, agility, and balance were evaluated through the following measurements: time required to run 1.5 km, physical efficiency index (PEI), vital capacity (ℓ), push-ups (reps/2 min), sit-ups (reps/2 min), back strength (kg), grip strength (kg), sit and reach distance (cm), vertical jumps (cm), whole body reaction time (ms), side steps (reps/30 s), and maximum time of standing on 1 foot with closed eyes (s). The odds ratios (OR) (95% confidence interval [CI]) of the BOG and WOG for the 1.5-km run were 0.367 (0.192-0.701) and 0.168 (0.037-0.773), respectively; of the BWOG and WOG for vital capacity were 5.900 (1.298-26.827) and 5.364 (1.166-24.670), respectively; of the BOG for push-ups was 0.517 (0.279-0.959); of the WOG for back strength was 0.206 (0.045-0.945); of the BWOG and BOG for grip strength were 5.973 (1.314-27.157) and 2.036 (1.089-3.807), respectively; and of the BOG for the whole body reaction time was 0.405 (0.212-0.774), as compared to the NG. We conclude that all 3 types of obesity (classified into the BWOG, BOG, and WOG) result in reduced cardiorespiratory and muscular endurance, but increased muscular strength and vital capacity.