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Comparative Assessment of Linear Regression and Machine Learning for Analyzing the Spatial Distribution of Ground-level NO2 Concentrations: A Case Study for Seoul, Korea (서울 지역 지상 NO2 농도 공간 분포 분석을 위한 회귀 모델 및 기계학습 기법 비교)

  • Kang, Eunjin;Yoo, Cheolhee;Shin, Yeji;Cho, Dongjin;Im, Jungho
    • Korean Journal of Remote Sensing
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    • v.37 no.6_1
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    • pp.1739-1756
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    • 2021
  • Atmospheric nitrogen dioxide (NO2) is mainly caused by anthropogenic emissions. It contributes to the formation of secondary pollutants and ozone through chemical reactions, and adversely affects human health. Although ground stations to monitor NO2 concentrations in real time are operated in Korea, they have a limitation that it is difficult to analyze the spatial distribution of NO2 concentrations, especially over the areas with no stations. Therefore, this study conducted a comparative experiment of spatial interpolation of NO2 concentrations based on two linear-regression methods(i.e., multi linear regression (MLR), and regression kriging (RK)), and two machine learning approaches (i.e., random forest (RF), and support vector regression (SVR)) for the year of 2020. Four approaches were compared using leave-one-out-cross validation (LOOCV). The daily LOOCV results showed that MLR, RK, and SVR produced the average daily index of agreement (IOA) of 0.57, which was higher than that of RF (0.50). The average daily normalized root mean square error of RK was 0.9483%, which was slightly lower than those of the other models. MLR, RK and SVR showed similar seasonal distribution patterns, and the dynamic range of the resultant NO2 concentrations from these three models was similar while that from RF was relatively small. The multivariate linear regression approaches are expected to be a promising method for spatial interpolation of ground-level NO2 concentrations and other parameters in urban areas.

The Scope and the Meaning of 'Time of Arrival' in Carriage of Passengers by Air : Focused on the Germanwings GmbH v. Ronny Henning, Case C-452/13 (2014). (항공여객운송에서의 지연보상과 도착시각의 의미 - EU 사법재판소 2014. 9. 14. 판결(ECLI:EU:C:2014:2141)을 중심으로 -)

  • Sur, Ji-Min
    • The Korean Journal of Air & Space Law and Policy
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    • v.33 no.2
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    • pp.267-290
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    • 2018
  • This paper reviews and criticizes the EU Case of C-452/13, Germanwings GmbH v. Ronny Henning. Under this case, Ronny Henning later sued Lufthansa's budget carrier Germanwings after it refused to pay him 250 euros compensation for a delay he said totalled more than three hours. Germanwings, however, maintained his flight had arrived only two hours and 58 minutes behind schedule. In those circumstances, the following question to the European Court of Justice (ECJ) for a preliminary ruling: What time is relevant for the term time of arrival used in Articles 2, 5 and 7 of Regulation [No 261/2004]: (a) the time that the aircraft lands on the runway (touchdown); (b) the time that the aircraft reaches its parking position and the parking brakes are engaged or the chocks have been applied (in-block time); (c) the time that the aircraft door is opened; (d) a time defined by the parties in the context of party autonomy? ECJ says that the situation of passengers on a flight does not change substantially when their aircraft touches down on the runway at the destination airport, when that aircraft reaches its parking position and the parking brakes are engaged or when the chocks are applied, as the passengers continue to be subject, in the enclosed space in which they are sitting, to various constraints. Therefore, it is only when the passengers are permitted to leave the aircraft and the order is given to that effect to open the doors of the aircraft that the passengers may in principle resume their normal activities without being subject to those constraints. ECJ rules that it is apparent that Articles 2, 5 and 7 of Regulation No 261/2004 must be interpreted as meaning that the concept of 'arrival time', which is used to determine the length of the delay to which passengers on a flight have been subject, corresponds to the time at which at least one of the doors of the aircraft is opened, the assumption being that, at that moment, the passengers are permitted to leave the aircraft.

Generation of Daily High-resolution Sea Surface Temperature for the Seas around the Korean Peninsula Using Multi-satellite Data and Artificial Intelligence (다종 위성자료와 인공지능 기법을 이용한 한반도 주변 해역의 고해상도 해수면온도 자료 생산)

  • Jung, Sihun;Choo, Minki;Im, Jungho;Cho, Dongjin
    • Korean Journal of Remote Sensing
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    • v.38 no.5_2
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    • pp.707-723
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    • 2022
  • Although satellite-based sea surface temperature (SST) is advantageous for monitoring large areas, spatiotemporal data gaps frequently occur due to various environmental or mechanical causes. Thus, it is crucial to fill in the gaps to maximize its usability. In this study, daily SST composite fields with a resolution of 4 km were produced through a two-step machine learning approach using polar-orbiting and geostationary satellite SST data. The first step was SST reconstruction based on Data Interpolate Convolutional AutoEncoder (DINCAE) using multi-satellite-derived SST data. The second step improved the reconstructed SST targeting in situ measurements based on light gradient boosting machine (LGBM) to finally produce daily SST composite fields. The DINCAE model was validated using random masks for 50 days, whereas the LGBM model was evaluated using leave-one-year-out cross-validation (LOYOCV). The SST reconstruction accuracy was high, resulting in R2 of 0.98, and a root-mean-square-error (RMSE) of 0.97℃. The accuracy increase by the second step was also high when compared to in situ measurements, resulting in an RMSE decrease of 0.21-0.29℃ and an MAE decrease of 0.17-0.24℃. The SST composite fields generated using all in situ data in this study were comparable with the existing data assimilated SST composite fields. In addition, the LGBM model in the second step greatly reduced the overfitting, which was reported as a limitation in the previous study that used random forest. The spatial distribution of the corrected SST was similar to those of existing high resolution SST composite fields, revealing that spatial details of oceanic phenomena such as fronts, eddies and SST gradients were well simulated. This research demonstrated the potential to produce high resolution seamless SST composite fields using multi-satellite data and artificial intelligence.

Development and Testing of a RIVPACS-type Model to Assess the Ecosystem Health in Korean Streams: A Preliminary Study (저서성 대형무척추동물을 이용한 RIVPACS 유형의 하천생태계 건강성 평가법 국내 하천 적용성)

  • Da-Yeong Lee;Dae-Seong Lee;Joong-Hyuk Min;Young-Seuk Park
    • Korean Journal of Ecology and Environment
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    • v.56 no.1
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    • pp.45-56
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    • 2023
  • In stream ecosystem assessment, RIVPACS, which makes a simple but clear evaluation based on macroinvertebrate community, is widely used. In this study, a preliminary study was conducted to develop a RIVPACS-type model suitable for Korean streams nationwide. Reference streams were classified into two types(upstream and downstream), and a prediction model for macroinvertebrates was developed based on each family. A model for upstream was divided into 7 (train): 3 (test), and that for downstream was made using a leave-one-out method. Variables for the models were selected by non-metric multidimensional scaling, and seven variables were chosen, including elevation, slope, annual average temperature, stream width, forest ratio in land use, riffle ratio in hydrological characteristics, and boulder ratio in substrate composition. Stream order classified 3,224 sites as upstream and downstream, and community compositions of sites were predicted. The prediction was conducted for 30 macroinvertebrate families. Expected (E) and observed fauna (O) were compared using an ASPT biotic index, which is computed by dividing the BMWPK score into the number of families in a community. EQR values (i.e. O/E) for ASPT were used to assess stream condition. Lastly, we compared EQR to BMI, an index that is commonly used in the assessment. In the results, the average observed ASPT was 4.82 (±2.04 SD) and the expected one was 6.30 (±0.79 SD), and the expected ASPT was higher than the observed one. In the comparison between EQR and BMI index, EQR generally showed a higher value than the BMI index.

Comparison of In Vitro, Ex Vivo, and In Vivo Antibacterial Activity Test Methods for Hand Hygiene Products (손 위생 제품에 대한 in vitro, ex vivo, in vivo 항균 시험법 비교)

  • Daeun Lee;Hyeonju Yeo;Haeyoon Jeong
    • Journal of Food Hygiene and Safety
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    • v.39 no.1
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    • pp.35-43
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    • 2024
  • Numerous methods have been applied to assess the antibacterial effectiveness of hand hygiene products. However, the different results obtained through various evaluation methods have complicated our understanding of the real efficacy of the products. Few studies have compared test methods for assessing the efficacy of hand hygiene products. In particular, reports on ex vivo pig skin testing are limited. This study aimed to compare and characterize the methodologies applied for evaluating hand hygiene products, involving in vitro, ex vivo, and in vivo approaches, applicable to both leave-on sanitizers and wash-off products. Our further aim was to enhance the reliability of ex vivo test protocols by identifying influential factors. We performed an in vitro method (EN1276) and an in vivo test (EN1499 and ASTM2755) with at least 20 participants, against Serratia marcescens or Escherichia coli and Staphylococcus aureus. For the ex vivo experiment, we used pig skin squares prepared in the same way as those used in the in vivo test method and determined the optimal treated sample volumes for sanitizers and the amount of water required to wash off the product. The hand sanitizers showed at least a 5-log reduction in bacterial load in the in vitro test, while they showed little antibacterial activity in the in vivo and ex vivo tests, particularly those with a low alcohol content. For the hand wash products, the in vitro test was limited because of bubble formation or the high viscosity of the products and it showed low antibacterial activity of less than a 1-log reduction against E. coli. In contrast, significantly higher log reductions were observed in ex vivo and in vivo tests, consistently demonstrating these results across the two methods. Our findings revealed that the ex vivo and in vivo tests reflect the two different antibacterial mechanisms of leave-on and wash-off products. Our proposed optimized ex vivo test was more rapid and more precise than the in vitro test to evaluate antibacterial results.

Analysis of the Impact of Satellite Remote Sensing Information on the Prediction Performance of Ungauged Basin Stream Flow Using Data-driven Models (인공위성 원격 탐사 정보가 자료 기반 모형의 미계측 유역 하천유출 예측성능에 미치는 영향 분석)

  • Seo, Jiyu;Jung, Haeun;Won, Jeongeun;Choi, Sijung;Kim, Sangdan
    • Journal of Wetlands Research
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    • v.26 no.2
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    • pp.147-159
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    • 2024
  • Lack of streamflow observations makes model calibration difficult and limits model performance improvement. Satellite-based remote sensing products offer a new alternative as they can be actively utilized to obtain hydrological data. Recently, several studies have shown that artificial intelligence-based solutions are more appropriate than traditional conceptual and physical models. In this study, a data-driven approach combining various recurrent neural networks and decision tree-based algorithms is proposed, and the utilization of satellite remote sensing information for AI training is investigated. The satellite imagery used in this study is from MODIS and SMAP. The proposed approach is validated using publicly available data from 25 watersheds. Inspired by the traditional regionalization approach, a strategy is adopted to learn one data-driven model by integrating data from all basins, and the potential of the proposed approach is evaluated by using a leave-one-out cross-validation regionalization setting to predict streamflow from different basins with one model. The GRU + Light GBM model was found to be a suitable model combination for target basins and showed good streamflow prediction performance in ungauged basins (The average model efficiency coefficient for predicting daily streamflow in 25 ungauged basins is 0.7187) except for the period when streamflow is very small. The influence of satellite remote sensing information was found to be up to 10%, with the additional application of satellite information having a greater impact on streamflow prediction during low or dry seasons than during wet or normal seasons.

Determinants of Consumer Responses to Retail Out-of-Stocks (점포내 품절상황에서 소비자 반응행동유형별 결정요인)

  • Chun, Dal-Young;Choi, Jong-Rae;Joo, Young-Jin
    • Journal of Distribution Research
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    • v.16 no.4
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    • pp.29-64
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    • 2011
  • Overview of Research: Product availability is one of important competences of store to fulfill consumer needs. If stock-outs which means a product what consumer wants to buy is not available occurs, consumer will face decision-making uncertainty that leads to consumer's negative responses such as consumer dissatisfaction on store. Stockouts was much studied in the field of academia as well as practice in other countries. However, stock-outs has not been researched at all in Marketing and/or Distribution area in Korea. The main objectives of this study are to find out determinants of consumer responses such as Substitute, Delay, and Leave(SDL) when consumer encounters out-of-stock situation and then to examine the effects of these factors on consumer responses. Specifically, this study focuses on situational characteristics(e.g., purchase urgency and surprise), store characteristics (e.g., product assortment and store convenience), and consumer characteristics (e.g., brand loyalty and store loyalty). Then, this study empirically investigates relationships these factors with consumers behaviors such as product substitution, purchase delay, and store switching.

    shows the research model of this study. To accomplish above-mentioned research objectives, the following ten hypotheses were proposed and verified : ${\bullet}$ H 1 : When out-of-stock situation occurs, purchase urgency will increase product substitution but will decrease purchase delay and store switching among consumer responses. ${\bullet}$ H 2 When out-of-stock situation occurs, surprise will decrease product substitution and purchase delay but will Increase store switching among consumer responses. ${\bullet}$ H 3 : When out-of-stock situation occurs, purchase quantities will increase product substitution and store switching but will decrease purchase delay among consumer responses. ${\bullet}$ H 4 : When out-of-stock situation occurs, pre-purchase plan will decrease product substitution but will increase purchase delay and store switching among consumer responses. ${\bullet}$ H 5 : When out-of-stock situation occurs, product assortment will increase product substitution but will decrease purchase delay and store switching among consumer responses. ${\bullet}$ H 6 : When out-of-stock situation occurs, competitive store price image will increase product substitution and purchase delay but will decrease store switching among consumer responses. ${\bullet}$ H 7 : When out-of-stock situation occurs, store convenience will increase product substitution but will decrease purchase delay and store switching among consumer responses. ${\bullet}$ H 8 : When out-of-stock situation occurs, salesperson services will increase product substitution but will decrease purchase delay and store switching among consumer responses. ${\bullet}$ H 9 : When out-of-stock situation occurs, brand loyalty will decrease product substitution but will increase purchase delay and store switching among consumer responses. ${\bullet}$ H 10 When out-of-stock situation occurs, store loyalty will increase product substitution and purchase delay but will decrease store switching among consumer responses. Analysis: Data were collected from 353 respondents who experienced out-of-stock situations in various store types such as large discount stores, supermarkets, etc. Research model and hypotheses were verified using multinomial logit(MNL) analysis. Results and Implications: is the estimation results of l\1NL model, and
    shows the marginal effects for each determinant to consumer's responses(SDL). Significant statistical results were as follows. Purchase urgency, purchase quantities, pre-purchase plan, product assortment, store price image, brand loyalty, and store loyalty were turned out to be significant determinants to influence consumer alternative behaviors in case of out-of-stock situation. Specifically, first, product substitution behavior was triggered by purchase urgency, surprise, purchase quantities, pre-purchase plan, product assortment, store price image, brand loyalty, and store loyalty. Second, purchase delay behavior was led by purchase urgency, purchase quantities, and brand loyalty. Third, store switching behavior was influenced by purchase urgency, purchase quantities, pre-purchase plan, product assortment, store price image, brand loyalty, and store loyalty. Finally, when out-of-stock situation occurs, store convenience and salesperson service did not have significant effects on consumer alternative responses.

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  • The Study about Problem in the course of Education of Special Guard (특수경비원 교육훈련실태 및 발전방안에 관한 연구)

    • Kang, Gil-Hoon
      • Korean Security Journal
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      • no.6
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      • pp.291-326
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      • 2003
    • The first, Improvement of education training condition Education training is influenced by facilities, environment around. according to questionnaire, it is very poor, we should set up a training institute as soon as possible. The second, Improvement of education training contents In working as special guard, they do not feel the need of curriculums like bayonet fencing, criminal law, and so on. accordingly we should adjust the contents of educaton training. The third, Improvement of education training course People were satisfied with the contents of lectures and educator more than half to some degree, but there was a question of time, communication, contents. we should try to remedy things like this. The fourth, Adjustment of education training time The 60% people of all were not satisfied with the time of education training about new duty. we need to intensify and oversee a duty training and the restructure of training time. The fifth, Fairness of valuation reward and punishment in education training The 80% people of all had the bad feeling against reward and punishment, so we tried to let fairness of valuation, reward and punishment completed by educational institution. The sixth, Establishment of the institution for special guard special guard have to be raised by special institution, but lacking of educational program, educational facility, educational Environment, university took the place of government as institution in raising special guard, education still leave much to be desired. so to develop the industry of a civil security, government or a guard association will set up the school of training, education, system about civil security as a whole. The seventh, Improvement of education training form People have to be taught for 80 hours in education training. according to questionnaire, over 75%people wanted to lodge at education accommodation, so in doing education training, we need to improve a system and form. The eighth, Operation of education training suitable for a characteristic in jobs In the education of 80 hours, common courses will need to be carried out together, depending on class, the object of national facility, inspection and practice will need to be done. maybe this can be the improvement of growing up education training. In the result of the study, we need to build up the satisfaction of education training through a lot of opinion like program, system, circumstances. Keep in mind that the paper was a few of problems because of the limit of the survey of 132 peoples, accordingly we try to collect a survey related with this around country. especially this will need to be asked for harmony between the law and the background of system. in the future, to develop the special guard service, increase the demand of this service, have to raised the expert and the special guard service has to enlarge.

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    Phytochemical Constituents from the Leaves of Soybean [Glycine max (L.) Merr.]

    • Lee, Jin-Hwan;Baek, In-Youl;Choung, Myoung-Gun;Ha, Tae-Joung;Han, Won-Young;Cho, Kye-Man;Ko, Jong-Min;Jeong, Seong-Hun;Oh, Ki-Won;Park, Keum-Yong;Park, Ki-Hun
      • Food Science and Biotechnology
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      • v.17 no.3
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      • pp.578-586
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      • 2008
    • Phytochemicals study from the leaves of soybean [Glycine max (L.) Merr.], one of Korean edible plant materials were investigated through various chromatographic procedures. The methanolic leaves extracts of soybean yielded 16 phytochemicals, including 5 isoflavones 1-5, 3 flavones 6-8, 1 flavonol 9, 2 pterocarpans 10 and 11, 2 phenolic compounds 12 and 13, 2 phytosterols 14 and 15, and 1 sugar alcohol 16. The structures were fully characterized by analysis of physical and spectral data and were defined clearly as 4,5,7-trihydroxyisoflavone (1), 4,5,7-trihydroxyisoflavone-7-O-$\beta$-D-glucopyranoside (2), 4,7-dihydroxy-6-methoxyisoflavone (3), 4,7-dihydroxyisoflavone (4), 4,7-dihydroxyisoflavone-7-O-$\beta$-D-glucopyranoside (5), 5,7,4'-trihydroxyflavone (6), 3',4',5,7-tetrahydroxyflavone (7), 3',4',5-trihydroxyflavone-7-O-$\beta$-D-glucopyranoside (8), 3,4',5,7-tetrahydroxyflavonol (9), coumestrol (10), glyceofuran (11), 4-hydroxybenzoic acid (12), methyl-4-hydroxybenzoate (13), soyasapogenol B (14), stigmasterol (15), and D-mannitol (16), respectively. Among them, phytochemicals 7-16 were reported for the first time on the isolation and confirmation from the leaves of this species. These results suggest that the leaves extracts of soybean may possess possible health related benefits to human due to the isolated phytochemicals 1-16 which have been well known potential effects on various chronic diseases.

    Effect of Changing Amniotic Fluid Osmolarity on the $Li^+$ Transport Through the Membrane Surrounding Amniotic Fluid in the Rabbit

    • Chang, Jin-Keun;Lee, Sang-Jin;Sung, Ho-Kyung
      • The Korean Journal of Physiology
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      • v.27 no.1
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      • pp.13-25
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      • 1993
    • To study the regulation of amniotic fluid volume and electrolyte concentration by the Membranes surrounding the amniotic fluid, the rate of $Li^+$ disappearance from amniotic sac of expired fetuses were examined while increasing the amniotic volume and osmolarity in rabbits. After intraamniotic injection of 1 ml isosmotic saline (about 20% of the amniotic fluid volume) containing 15 mM LiCl and 0.5 g/L Censored, the time courses of $Li^+$ and Censored disappearance were determined. From there the $Li^+$ clearance through the extrafetal routes was estimated and compared with that obtained from living fetuses. The volume, $Na^+$ concentration and osmolarity of amniotic fluid were measured and their relationships with $Li^+$ disappearance were evaluated. The fellowing results were obtained: 1. The rate of disappearance from amniotic fluid of living fetuses during the first 30 minutes was strikingly higher for $Li^+$ than for Censored, suggesting that extrafetal routes exist. At 60 and 90 minutes, however, the disappearance rate of $Li^+$ was less than that of Censored, suggesting the possibility of $Li^+$ reentry through fetal urination. 2. The disappearance of $Li^+$ from the amniotic fluid of the expired fetus was substantial, although lower than that of living fetuses, throughout the experimental period. 3. The $Na^+$ concentration and the osmolarity of the amniotic fluid of expired fetus measured 30 minutes after an intraamniotic injection of isoosmotic saline showed wide variation, but thereafter they changed gradually towards the normal extracellular fluid level. 4. When the amniotic fluid was iso- or hyposmolar, the rate of $Li^+$ disappearance from the amniotic fluid of the expired fetuses showed little variation. However, when the amniotic fluid was hyperosmolar, the rate at 30 minutes was markedly lower than those of isosmotic or hyposmotic amniotic fluid. At 90 minutes, the rate of $Li^+$ disappearance in hyperosmolar fluid reached a similar level to the rate in isosmolar fluid. 5. The intraamniotic injection of 400 mOsm/L saline solution decreased the disappearance rate of $Li^+$ from expired fetuses, while the injection of mannitol into the maternal vein induced no significant change. From these results it is concluded that: 1) a significant amount of $Li^+$ may leave the amniotic fluid via filtration through the membranes surrounding the amniotic fluid, 2) during hyperosmolar challenge to amniotic fluid, osmotic bulk flow might counteract the filterable loss, and 3) $Li^+$ disappearance might continue even after the volume and osmolarity of the amniotic fluid have recovered to control values.

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