• Magazine of the Korean Society of Agricultural Engineers
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• v.16 no.1
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• pp.3225-3262
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• 1974

The purposes of this thesis are to clarify experimentally the variation of ground water temperature in tube wells during the irrigation period of paddy rice, and the effect of ground water irrigation on the growth, grain yield and yield components of the rice plant, and, furthermore, when and why the plant is most liable to be damaged by ground water, and also to find out the effective ground water irrigation methods. The results obtained in this experiment are as follows; 1. The temperature of ground water in tube wells varies according to the location, year, and the depth of the well. The average temperatures of ground water in a tubewells, 6.3m, 8.0m deep are $14.5^{\circ}C$ and $13.1^{\circ}C$, respercively, during the irrigation period of paddy rice (From the middle of June to the end of September). In the former the temperature rises continuously from $12.3^{\circ}C$ to 16.4$^{\circ}C$ and in the latter from $12.4^{\circ}C$ to $13.8^{\circ}C$ during the same period. These temperatures are approximately the same value as the estimated temperatures. The temperature difference between the ground water and the surface water is approximately $11^{\circ}C$. 2. The results obtained from the analysis of the water quality of the "Seoho" reservoir and that of water from the tube well show that the pH values of the ground water and the surface water are 6.35 and 6.00, respectively, and inorganic components such as N, PO4, Na, Cl, SiO2 and Ca are contained more in the ground water than in the surface water while K, SO4, Fe and Mg are contained less in the ground water. 3. The response of growth, yield and yield components of paddy rice to ground water irrigation are as follows; (l) Using ground water irrigation during the watered rice nursery period(seeding date: 30 April, 1970), the chracteristics of a young rice plant, such as plant height, number of leaves, and number of tillers are inferior to those of young rice plants irrigated with surface water during the same period. (2) In cases where ground water and surface water are supplied separately by the gravity flow method, it is found that ground water irrigation to the rice plant delays the stage at which there is a maximum increase in the number of tillers by 6 days. (3) At the tillering stage of rice plant just after transplanting, the effect of ground water irrigation on the increase in the number of tillers is better, compared with the method of supplying surface water throughout the whole irrigation period. Conversely, the number of tillers is decreased by ground water irrigation at the reproductive stage. Plant height is extremely restrained by ground water irrigation. (4) Heading date is clearly delayed by the ground water irrigation when it is practised during the growth stages or at the reproductive stage only. (5) The heading date of rice plants is slightly delayed by irrigation with the gravity flow method as compared with the standing water method. (6) The response of yield and of yield components of rice to ground water irrigation are as follows: \circled1 When ground water irrigation is practised during the growth stages and the reproductive stage, the culm length of the rice plant is reduced by 11 percent and 8 percent, respectively, when compared with the surface water irrigation used throughout all the growth stages. \circled2 Panicle length is found to be the longest on the test plot in which ground water irrigation is practised at the tillering stage. A similar tendency as that seen in the culm length is observed on other test plots. \circled3 The number of panicles is found to be the least on the plot in which ground water irrigation is practised by the gravity flow method throughout all the growth stages of the rice plant. No significant difference is found between the other plots. \circled4 The number of spikelets per panicle at the various stages of rice growth at which_ surface or ground water is supplied by gravity flow method are as follows; surface water at all growth stages‥‥‥‥‥ 98.5. Ground water at all growth stages‥‥‥‥‥‥62.2 Ground water at the tillering stage‥‥‥‥‥ 82.6. Ground water at the reproductive stage ‥‥‥‥‥ 74.1. \circled5 Ripening percentage is about 70 percent on the test plot in which ground water irrigation is practised during all the growth stages and at the tillering stage only. However, when ground water irrigation is practised, at the reproductive stage, the ripening percentage is reduced to 50 percent. This means that 20 percent reduction in the ripening percentage by using ground water irrigation at the reproductive stage. \circled6 The weight of 1,000 kernels is found to show a similar tendency as in the case of ripening percentage i. e. the ground water irrigation during all the growth stages and at the reproductive stage results in a decreased weight of the 1,000 kernels. \circled7 The yield of brown rice from the various treatments are as follows; Gravity flow; Surface water at all growth stages‥‥‥‥‥‥514kg/10a. Ground water at all growth stages‥‥‥‥‥‥428kg/10a. Ground water at the reproductive stage‥‥‥‥‥‥430kg/10a. Standing water; Surface water at all growh stages‥‥‥‥‥‥556kg/10a. Ground water at all growth stages‥‥‥‥‥‥441kg/10a. Ground water at the reproductive stage‥‥‥‥‥‥450kg/10a. The above figures show that ground water irrigation by the gravity flow and by the standing water method during all the growth stages resulted in an 18 percent and a 21 percent decrease in the yield of brown rice, respectively, when compared with surface water irrigation. Also ground water irrigation by gravity flow and by standing water resulted in respective decreases in yield of 16 percent and 19 percent, compared with the surface irrigation method. 4. Results obtained from the experiments on the improvement of ground water irrigation efficiency to paddy rice are as follows; (1) When the standing water irrigation with surface water is practised, the daily average water temperature in a paddy field is 25.2$^{\circ}C$, but, when the gravity flow method is practised with the same irrigation water, the daily average water temperature is 24.5$^{\circ}C$. This means that the former is 0.7$^{\circ}C$ higher than the latter. On the other hand, when ground water is used, the daily water temperatures in a paddy field are respectively 21.$0^{\circ}C$ and 19.3$^{\circ}C$ by practising standing water and the gravity flow method. It can be seen that the former is approximately 1.$0^{\circ}C$ higher than the latter. (2) When the non-water-logged cultivation is practised, the yield of brown rice is 516.3kg/10a, while the yield of brown rice from ground water irrigation plot throughout the whole irrigation period and surface water irrigation plot are 446.3kg/10a and 556.4kg/10a, respectivelely. This means that there is no significant difference in yields between surface water irrigation practice and non-water-logged cultivation, and also means that non-water-logged cultivation results in a 12.6 percent increase in yield compared with the yield from the ground water irrigation plot. (3) The black and white coloring on the inside surface of the water warming ponds has no substantial effect on the temperature of the water. The average daily water temperatures of the various water warming ponds, having different depths, are expressed as Y=aX+b, while the daily average water temperatures at various depths in a water warming pond are expressed as Y=a(b)x (where Y: the daily average water temperature, a,b: constants depending on the type of water warming pond, X; water depth). As the depth of water warning pond is increased, the diurnal difference of the highest and the lowest water temperature is decreased, and also, the time at which the highest water temperature occurs, is delayed. (4) The degree of warming by using a polyethylene tube, 100m in length and 10cm in diameter, is 4~9$^{\circ}C$. Heat exchange rate of a polyethylene tube is 1.5 times higher than that or a water warming channel. The following equation expresses the water warming mechanism of a polyethylene tube where distance from the tube inlet, time in day and several climatic factors are given: {{{{ theta omega (dwt)= { a}_{0 } (1-e- { x} over { PHI v })+ { 2} atop { SUM from { { n}=1} { { a}_{n } } over { SQRT { 1+ {( n omega PHI) }^{2 } } } } LEFT { sin(n omega t+ { b}_{n }+ { tan}^{-1 }n omega PHI )-e- { x} over { PHI v }sin(n omega LEFT ( t- { x} over {v } RIGHT ) + { b}_{n }+ { tan}^{-1 }n omega PHI ) RIGHT } +e- { x} over { PHI v } theta i}}}}{{{{ { theta }_{$\infty$ }(t)= { { alpha theta }_{a }+ { theta }_{ w'} +(S- { B}_{s } ) { U}_{w } } over { beta } , PHI = { { cpDU}_{ omega } } over {4 beta } }}}} where $\theta$$\omega$; discharged water temperature($^{\circ}C$) $\theta$a; air temperature ($^{\circ}C$) $\theta$$\omega$';ponded water temperature($^{\circ}C$) s ; net solar radiation(ly/min) t ; time(tadian) x; tube length(cm) D; diameter(cm) ao,an,bn;constants determined from $\theta$$\omega$(t) varitation. cp; heat capacity of water(cal/$^{\circ}C$ ㎥) U,Ua; overall heat transfer coefficient(cal/$^{\circ}C$ $\textrm{cm}^2$ min-1) $\omega$;1 velocity of water in a polyethylene tube(cm/min) Bs ; heat exchange rate between water and soil(ly/min)

• Journal of The Korean Association For Science Education
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• v.32 no.1
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• pp.95-112
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• 2012

The research evaluated the effects of the improvements in scientific inquiry for elementary school students and focused on the development and application of the explicit and reflective learning strategy through observation and classification. The explicit and reflective learning strategy was modified and completed with the review of the experts after the development of the draft based on the theoretical approach. The students were evaluated for their academic achievements in scientific inquiry skills before and after taking the course. The results were as follows: First, the steps of the developed learning strategy (1) to motivate, (2) to explore reflectively, (3) to guide explicitly, (4) to inquire explicitly, and (5) to verify reflectively were set to reflect the verification. Second, the results of applying the developed model to the lessons based on the quantitative analysis was effective for observation and classification skills in the quest for improved performance of the whole (the sum of observation and classification, inquiry skills) and the observed features, but there was no effect on classification. Also, the lessons applied the developed teaching strategy and showed effectiveness in improving academic achievement. Particularly in analyzing the relationship between the academic achievement and exploration capabilities, in order to improve academic achievement, the importance of improving inquiry skills was found. Third, the qualitative analysis of teaching and learning strategy developed by applying the lessons of this teacher guide and small group activities through the explicit and reflective observation and classification of the student learning activities showed the significant improvement of ability of the scientific inquiry skills. In addition to the improvement in the abilities of the classification showed after the formation of the most basic observation skills of the scientific inquiry.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.5
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• pp.578-583
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• 2010

Acid rain and its problem to environment such as acid precipitation and environmental problems related to the air pollution in East Asia has been emerging. To evaluate the acidity and chemical characteristics of rainwater precipitated in western Korea, Suwon and Taean, its pH and ion concentrations were investigated during farming season (April to November) in 2009. Also, ion composition and cation-affected neutralization were determined to evaluate the contribution of cations on the acidity of rainwater. Ion and electrical conductivity between the measured and the estimated showed high correlation. The $Na^+$ in rainwater was the main cation followed by ${NH_4}^+>Ca^{2+}>H^+>Mg^{2+}>K^+$. Sum of $Na^+$ and ${NH_4}^+$ contents was over 65% of total cations contents. In the case of anions, the concentration was in order of ${SO_4}^{2-}>{NO_3}^->Cl^-$. The ${SO_4}^{2-}$ among anions in rainwater composed about 61%, which showed on average 130.2 ${\mu}eq\;L^{-1}$ and 121.3 ${\mu}eq\;L^{-1}$ during monitoring at Suwon and Taean, respectively. Also, 89.6 and 88.6% of soluble sulfate in rainwater at Suwon and Taean area was NSS-${SO_4}^{2-}$ (Non-Sea Salt sulfate). Especially, ${NH_4}^+$ and $Ca^{2+}$ contributed greatly in neutralizing the acid rain in dry season. Total nitrogen content flowed into soil from rain was around 1~2 kg $ha^{-1}$ in each month, but in July at Suwon, it reached 6 kg $ha^{-1}$ due to heavy rain (over 7.3 mm).

• Journal of the Korea Organic Resources Recycling Association
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• v.24 no.4
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• pp.59-68
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• 2016

The application of the Life Cycle Assessment (LCA) methodology to assess the environmental impact of rapeseed cultivation in winter fallow after harvesting rice was investigated and compared with barley cultivation in crop rotation system. Data for input materials were collected and analyzed by 1 ton rapeseed and barley as functional unit. For the Life Cycle Impact Assessment (LCIA) the Eco-indicator 95 method has been chosen because this is well documented and regularly applied impact method. From the comparison of impact categories such as greenhouse effect, ozone depletion, acidification, heavy metals, carcinogens, summer smog, and energy resources for 1 ton of final product, emission potential from rapeseed was higher than that from barley. The range from 65 to 96% of these potential came from chemical fertilizer. On the other hand, eutrophication potential from barley was higher than that from rapeseed, mainly came from utilizing the chemical fertilizer. During the cultivation of barley and rape, environmental burden by heavy metals was evaluated by 0.5 Pt, larger than points from other impact categories. The sum of points from all impact categories in barley and rapeseed was calculated to be 0.78 Pt and 0.82 Pt, respectively. From the sensitivity analysis for barley and rapeseed, scenario 1 (crop responses to fertilization level) showed the environmental burden was continuously increased with the amount of fertilization in barley cultivation, while it was not increased only at the optimum crop responses to fertilization in rapeseed (R3). With these results, rapeseed cultivation in winter fallow paddy contributed to the amounts of environmental burden much more than barley cultivation. It is, however, highly determined that environmental weighted point resulted from evaluating both cultivation was not significantly different.

• Journal of Wetlands Research
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• v.7 no.2
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• pp.105-120
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• 2005

This study was carried out at Reed Marsh of Sihwa Lake from July 2003 to June 2004. We observed total(sum of maximum population) 5,752 individuals of 70 species including 12 species of ducks, 10 species of egrets, 6 species of wagtails and buntings, 4 species of eagles. The most dominant species was Spotbill Duck(Anas poecilorhyncha - 3,518 individuals, 61.16%), and other species were Mallard(Anas platyrhynchos - 540 individuals, 9.39%), Great Reed-Warbler(Acrocephalus arundinaceus - 217 individuals, 3.77%). Reed Marsh of Sihwa Lake were observed many kinds of protected species such as Great Bittern(Botaurus stellaris), Mandarin Duck(Aix galericulata), Chinese Sparrow Hawk (Accipiter soloensis), Eurasian Sparrow Hawk(Accipiter nisus), Japanese Buzzard(Buteo buteo), Hen Harrier(Circus cyaneus), Eurasian Hobby(Falco subbuteo), and Common Kestrel(Falco tinnunculus). Since the Reed Marsh of Sihwa Lake arrived many individuals of waterbird, crop damage by the waterbird occurred in the surrounding rice fields. It was an area adjacent to the reed marsh of sihwa lake such as Yoopori and Samhwari Bibongmyoun, Yamokri Maesongmyoun Hwaseong City. Bird of crop damage was ducks openly. The most species was Spot-billed Duck. Crop damage types by the Spot-billed Duck were grazing, used the grain up or lower in quality with step on the rice. Crop damage size was about 560bags of rice during the one month on August 2002. In 2003, After carrying out the various crop damage reduction countermeasures, which measured crop damage size in 2002's crop damage area. It happened about 152bags of rice during the two months from on August to September 2003. Migration routes of Spot-billed Duck were that it was migrated from up the sihwa lake to reed marsh. It took a rest at reed marsh and migrated the surrounding rice fields for the feeding action. In 2002, it was migrated direct from up the sihwa lake to in surrounding rice fields. But as environment of reed marsh was improved better than 2002, it was migrated to reed marsh because of reducing the energy attrition rate. Crop damage reduction countermeasures are get on ears to use explosion machine, searchlight, start-gun and patrol at regular intervals. Which was an effect short term. Indirect method is to make a feeding area of substitution at up the sihwa lake and reed marsh of sihwa lake.

• Journal of Aquaculture
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• v.13 no.4
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• pp.277-284
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• 2000

Rabbitfish hatchlings were given a mixed food of rotifers (Brachionus rotundiformis) and trochophore larvae of oyster. Only the oyster-trochophore larvae were found in the gut of 62-h old fish larvae. The fish larvae, fed on rotifer and ciliate alone did not survive. However, their survival increased to 3.3 % on the 10th day after hatching, when trochophore was supplemented. Corresponding with the accelerated growth, the number of rotifers consumed increased from 11 in a 5-day old fish to 165 in a IS-day old fish. In a field ecosystem containing live diatom, Nannochloropsis oculata, rotifers and copepods, fish larvae were shocked and the oyster's trochophore larvae were fed from 2 to 7 days after hatching. A total of 76,000 seedling were produced after 50 days of hatching with 12.7 % survival. Mean total length and body weight were 65.6 mm and 3.4 g, respectively. Growth of body length (BL), body height (BH), body weight (BW) and head length (HL) as a function of the total length (TL) showed regressional relationships as follows; BL=0.8565 TL+0.0852 ($t^2$=0.9996); BH=0.3207 TL - 0.5052 (($t^2$=0.9641) BW=0.0652 TL2.3508 (($t^2$=0.9925); HL=0.2595 TL - 0.1898 (($t^2$=0.9901)

• Journal of the East Asian Society of Dietary Life
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• v.25 no.1
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• pp.30-38
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• 2015

The purpose of this study was to compare energy intake according to expected body mass index (BMI) in adolescents. A total of 280 middle school students were divided into current or/and expected obesity groups (underweight group; UWG, normal weight group; NWG, and overweight group; OWG) by BMI to compare energy intake and perception on body shape and weight control. The average age of total subjects was 15 years, and the distributions of boys and girls were 52.5% and 47.5%, respectively. The distribution of boys and girls was not significantly different among current obesity groups but was among expected obesity groups (15% and 82% in UWG vs. 71.4% and 16.5% NWG vs. 13.6% and 1.5% in OWG; P<0.001), indicating that girls wanted to lose weight more than boys. For body shape, most subjects in current obesity groups responded "fitness" in UWG (38.7%), "fitness" and "slightly chubby" in NWG (45.5% and 39%), and "slightly chubby" in OWG (65.2%), showing a significant difference (P<0.001). For interest in weight control, most subjects responded "average" in current UWcinterested" in current OWG (52.2%), whereas they responded "very interested" in expected UWG (55.7%), "average" in expected NWG (51.2%), and "not interested" in expected OWG (45.5%), showing a significant difference (P<0.001). The percentage of subjects with experience with weight control was significantly high in current OWG (71.7%), NWG (51.2%) and UWG (34.2%) as well as in expected UWG (57.3%), NWG (40.2%) and OWG (36.4%) in descending order (P<0.001). The daily energy intake of total subjects was 2,057.1 kcal without any significant difference among current obesity groups. However, it was significantly lower in expected UWG than expected NWG and OWG (1,943.1 kcal vs. 2,165.0 kcal or/and 2,152.1 kcal; P<0.001). To sum up these results, girls wanted to lose weight more than boys. The more students wanted to lose weight, the greater their experience and interest in weight control and the lower their energy intake.

• Journal of Korean Society of Forest Science
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• v.106 no.2
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• pp.219-229
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• 2017

Forest road is an essential infrastructure for forest management such as the composition and management of forest resources, timber and forest byproduct production & transportation. It has recently been utilized forest recreation and forest sports as well as also forest pest control, forest fire prevention and evolution. When you build a forest road, the economic function in the forest is activated, so that it can result in the ripple effect of induced employment, value-added creation and production inducement. The purpose of this study is to analyze the impact caused by forest road construction occurring as the overall economy. For analysis it was applied to inter industry analysis method that is a method for analyzing the quantitative cross-correlation. The data were used in the Input-Output Tables In 2014, the Bank of Korea. When you build a forest road, economic effect due to the construction of the forest road is generated and economic effects are also generated due to the increase in the production of forest products after the construction of the forest road. Therefore, we will analyze the economic impact of the two effects. The estimated economic value of forest products, which is the economic effect of forest product cultivation, was calculated through some assumptions and the economic ripple effect was analyzed. The forest road construction sector is defined as land clearing and reclamation, and irrigation project construction and the forestry forest products sector is defined as the sum of raw timber, edible forest products and misc. forest products. In total, 32 sectors were classified, and except for the two sectors defined as forest road construction and forestry forest products, the remaining sectors were integrated according to the classification system of 30 integrated classifications of the Bank of Korea. As a result, the production inducement coefficient for forest construction was analyzed to be 2.767 and the production inducement coefficient for forestry forest products was analyzed to be 1.565. This means that 2,767 times the production of forest road construction investment is induced in the whole industry and the production of 1.562 times the amount of forestry forest products is caused by the whole industry as the production of forestry forest products increases. The value added inducement coefficient for forest road construction was 0.977 and the value added inducement coefficient for forestry forest products was 0.985. Forest road are essential infrastructure for forestry development and should be continuously invested because they are essential elements of timber production and forest byproduct production with functions such as forest management, forest recreation, forest sports, and town connection.

• Korean Journal of Environmental Agriculture
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• v.39 no.1
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• pp.10-19
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• 2020

BACKGROUND: This study was to carry out risk assessment of contamination of cadmium (Cd), lead (Pb), and inorganic arsenic (I-As) in agricultural products of 25 crops from the abandoned mine areas. The 36 typical investigation sites located in Gyeongbuk provincial area were selected by considering the heavy metal levels, that had been known that the amount of the heavy metals exceeded the contamination level based on the previous survey. METHODS AND RESULTS: Cadmium, lead, and total arsenic (T-As) concentrations were determined using microwave device and ICP-MS. Inorganic arsenic was determined by HPLC-ICP-MS. The limits of quantification for heavy metals were 0.59 ㎍/kg for Cd, 0.42 ㎍/kg for Pb, 0.55 ㎍/kg for T-As, and sum of As (III) (1.74 ㎍/kg) and As (V) (2.25 ㎍/kg) for I-As, respectively. The contents of Cd, Pb, and I-As (only rice) were N.D.-0.958 mg/kg, N.D.-0.227 mg/kg, and 0.082 mg/kg, respectively, in the agricultural products. For risk assessment, dietary exposures of heavy metals through usual intake were 5.20×10^-4-7.15×10⁰ ㎍/day for Cd, 7.00×10^-5-7.75×10^-1 ㎍/day for Pb, and 1.17×10¹ ㎍/day for I-As, taking 0.01-14.37%, 0.01-2.05%, and 15.16% as risk indices, respectively. CONCLUSION: It requires to consider the critical levels of heavy metals in agricultural products due to unexpectedly high levels in a few places, while concentrations of heavy metals in the samples were relatively low in most areas.

• Journal of Life Science
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• v.19 no.8
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• pp.1073-1080
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• 2009

A number of studies have demonstrated that the regular use of nonsteroidal anti-inflammatory drugs (NSAIDs) can reduce the risks of colorectal, oesophageal and lung cancers. NSAIDs have been shown to exert their anti-cancer effects through inducing apoptosis in cancer cells. The susceptibility of tumor cells to anti-tumor drug-induced apoptosis appears to depend on the balance between pro-apoptotic and anti-apoptotic programs such as nuclear factor kB (NF-kB), phosphatidylinositol 3-kinase (PI3K)-Akt/protein kinase B (PKB) and MEK1/2-ERK1/2 pathways. We examined the effects of pro-survival PI3K and ERK1/2 signal pathways on cell cycle arrest and apoptosis in response to NSAIDs including sulindac sulfide and NS398. We show that simultaneous inhibition of the Akt/PKB and ERK1/2 signal cascades could synergistically enhance the potential pro-apoptotic activities of sulindac sulfide and NS398. Similar enhancement was observed in cells treated with sulindac sulfide or NS398 and 100 ${\mu}$M genistein, an inhibitor of receptor tyrosine kinases (RTKs) that are upstream of PI3K and MEK1/2 signaling. We further demonstrate that NAG-1 is induced and plays a critical role(s) in apoptosis by NSAIDs-based combined treatment. In sum, our results show that combinatorialtreatment of sulindac sulfide or NS398 and genistein results in a highlysynergistic induction of apoptotic cell death to increase the chemopreventive effects of the NSAIDs, sulindac sulfide and NS398.