• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.199-199
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• 2016

In recent decades, climate change phenomenon has developed towards critical tendency and increased in both frequency, intensity and time which causes catastrophic damage in both people and property, especially in the field of agriculture and water resources. At the current, some researches in the world and Viet Nam studies on climate change impacts on the water resources sectors. Results of scientists'studies showed that climate change will seriously impact productivity, livelihoods and the environment on a global scale; especially large flood phenomena increasingly developing in intensity, drought more violently occurring in a long time. In recent years, the shortage of water supply for economic activity has started to happen with quite serious degree at the Viet Nam, especially in the northern mountainous provinces of Viet Nam.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.190-190
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• 2017

In recent decades, climate change phenomenon has developed towards critical tendency and increased in both frequency, intensity and time which causes catastrophic damage in both people and property, especially in the field of agriculture and water resources. At the current, some researches in the world and Viet Nam studies on climate change impacts on the water resources sectors. Results of scientists' studies showed that climate change will seriously impact productivity, livelihoods and the environment on a global scale; especially large flood phenomena increasingly developing in intensity, drought more violently occurring in a long time. In recent years, the shortage of water supply for economic activity has started to happen with quite serious degree at the Viet Nam, especially in the northern provinces of Viet Nam.

• Journal of Bio-Environment Control
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• v.29 no.1
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• pp.28-35
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• 2020

This study is to compare irrigation efficiency between sap flow sensor automated system (SF) and conventional irrigation system based on integrated solar radiation automated system (ISR) in tomato rockwool hydroponics. Total irrigated volumes was higher in the ISR system by 5.0L per plant, a lower drainage rate was found in the SF system, compared to the ISR system. There was no difference in shoot and fruit fresh weights, water use efficiency (WUE) and water amount consumed for producing 200g of tomato fruit. The daily average sap flow density (SFD) was closer to the change of solar irradiance (SI) in the plant grown under the SF system, compared to the ISR system. The correlation coefficient (r²) between the fruit diameter and the volumetric water content during the 56 and 82 days after transplant showed the SF treatment was higher than the ISR at night and daytime, and the correlation was higher at night time. The sap flow density and humidity deficit (HD) of SF treatment was related as closely as the solar irradiance. Further studies should demonstrate that SF irrigation system is a convenient method for hydroponic farmers with advantages, such as growth, higher yield, WUE, and accuracy.

• Asian Journal of Turfgrass Science
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• v.23 no.1
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• pp.9-22
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• 2009

Due to increasing concerns over issues with both water quantity and quality for turfgrass use, research was conducted to determine the response of five warm-season turfgrasses to deficit irrigation and to gain a better understanding of relative drought tolerance. St. Augustinegrass(Stenotaphrum secundatum [Walt.] Kuntze.) cultivars 'Floratam' and 'Palmetto', 'SeaIsle 1' seashore Paspalum(Paspalum vaginatumSwartz.), 'Empire' zoysiagrass(Zoysia japonica Steud.), and 'Pensacola' bahiagrass(Paspalum notatum Flugge) were established in lysimeters in the University of Florida Envirotron greenhouse facility in Gainesville. Irrigation was applied at100%, 80%, 60%, or 40% of evapotranspiration(ET). Evaluations included: a) shoot quality, leaf rolling, leaf firing; b) leaf relative water content(RWC), soil moisture content, chlorophyll content index(CCI), canopy photosynthesis(PS); c) multispectral reflectance(MSR); d) root distribution; and e) water use efficiency. Grasses irrigated at 100% and 80% of ET had no differences in visual quality, leaf rolling, leaf firing, RWC, CCI, and PS. Grasses irrigated at 60% of ET had higher values in physiological aspects than grasses irrigated at 40% of ET. 'Sealsle 1' and 'Palmetto' had a deeper root system than 'Empire' and 'Pensacola', while 'Floratam' had the least amount of root mass. Photosynthesis was positively correlated with visual assessments such as turf quality, leaf rolling, leaf firing, and sensor-based measurements such as CCI, soil moisture, and MSR. Reducing the amount of applied water by 20% did not reduce turfgrass quality and maintained acceptable physiological functioning.

• Journal of Plant Biotechnology
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• v.39 no.3
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• pp.154-162
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• 2012

This study was conducted to evaluate agronomic characteristics such as growth, quality, and yields of StMyb1R-1 transgenic potato and also to obtain the basic data for establishing assessment guidelines of transgenic potato. Three transgenic lines (Myb 1, Myb 2, and Myb 8) were cultivated under conventional irrigation, drought condition, and severe drought condition and were analyzed by comparing with wild type, non-transgenic cv. Superior. Myb 2 showed a different flower color from wild type and Myb 1 had much bigger secondary leaflets than wild type. Myb 1 and Myb 2 showed higher $P_2O_5$ content in both top and root zone and longer shaped tubers than wild type. In yield factors, transgenic lines had more tubers than wild type, however their yield decreases were severe because of the poor enlargement of tuber under water deficit condition. This tendency was noticeable in Myb 1 and Myb 2. In TR ratio, chlorophyll content, dry matter rate, and relative water content, there were no big differences between transgenic lines and wild type. Meanwhile, in phenotype, growth, quality, and yield factors, substantial equivalent was confirmed between Myb 8 and wild type. Then, Myb 8 showed the highest marketable tuber yield under conventional irrigation, while showed lower level than wild type under water deficit. Judged by this result, the enhancing droughttolerance by StMyb1R-1 gene might actually not mean the enhancement of photosynthesis or starch accumulation in tuber and, furthermore, not the yield improvement. More detailed research will be required to accurately understand the relationship between StMyb1R-1 and yield factors.

• Water Engineering Research
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• v.1 no.3
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• pp.243-256
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• 2000

This physically-based hydrologic model is developed to calculate the soil-moisture balance on paddy fields. This model consists of three modules; the first is the unsaturated module, the second is the rice evapotranspiration module with SPAC(soil-plant-atmospheric-continuum), and the third is the groundwater and open channel flows based upon the interrehtionship module. The model simulates the hydrlogical processes of infiltration, soil water storage, deep perocolation or echarge to the shallow water table, transpiration and evaporation from the soil surface and also the interrelationship of the groundwater and river flow exchange. To verify the applicability of the developed model, it was applied to the Kimjae Plains, located in the center of the Dongjin river basin in Korea, during the most serious drought season of 1994. The result shows that the estimated water net requirement was 757mm and the water deficit was about 5.9% in this area in 1994. This model can easily evaluate the irrigated water quantity and visualize the common crop demands and soil moisture conditions.

• Journal of Physiology & Pathology in Korean Medicine
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• v.25 no.4
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• pp.691-696
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• 2011

In order to the neuroprotective effect of electroacupuncture (EA), the present study examined the effects of electroacupuncture inacupoint ST36 (Stomach 36) on trimethyltin chloride (TMT)-induced cognitive impairments rat using the Morris water maze (MWM) task and immunohistochemistry staining. The rats were randomly divided into the following groups: naive rat (Normal), TMT injection rat (Control), TMT injection + EA treated rat inacupoint ST36 (ST36) and TMT injection + EA treated rat in non-acupoint, base of tail (Non-AC). Electroacupuncture (2Hz, 2mA, and 10 minutes)was applied either to the acupuncture point ST36 or the nonacupuncture point in the tail for the last 14 days. In the water maze test, the animals were trained to find a platform in a fixed position during 4d and then received 60s probe trial on the $5^{th}$ day following removal of platform from the pool. Rats with TMT injection showed impaired learning and memory of the tasks and treatment with EA in acupoint ST36 (P<0.05) produced a significant improvement in escape latency to find the platform after $2^{nd}$ day and retention trial in the Morris water maze. Consistent with behavioral data, treatment with EA in acupoint ST36 also significantly increased expression of Choline acetyltransferase (ChAT) and Acetylcholinesterase (AChE) immunoreactive neurons in the hippocampus compared to the Control group. These results demonstrated that EA in acupoint ST36 has a protective effect against TMT-induced neuronal and cognitive impairments. The present study suggests that EA in acupoint ST36 might be useful in the treatment of TMT-induced learning and memory deficit.

• Biomolecules & Therapeutics
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• v.20 no.1
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• pp.125-131
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• 2012

Impulsiveness is an important component of many psychiatric disorders including Attention-deficit/hyperactivity disorder (ADHD). Although the neurobiological basis of ADHD is unresolved, behavioral tests in animal models have become indispensable tools for improving our understanding of this disorder. In the punishment/extinction paradigm, impulsivity is shown by subjects that persevere with responding despite punishment or unrewarded responses. Exploiting this principle, we developed a new behavioral test that would evaluate impulsivity in the most validated animal model of ADHD of the Spontaneously Hypertensive rat (SHR) as compared with the normotensive "control" strain, the Wistar Kyoto rat (WKY). In this paradigm we call the Electro-Foot Shock aversive water Drinking test (EFSDT), water-deprived rats should pass over an electrified quadrant of the EFSDT apparatus to drink water. We reasoned that impulsive animals show increased frequency to drink water even with the presentation of an aversive consequence (electro-shock). Through this assay, we showed that the SHR was more impulsive than the WKY as it demonstrated more "drinking attempts" and drinking frequency. Methylphenidate, the most widely used ADHD medication, significantly reduced drinking frequency of both SHR and WKY in the EFSDT. Thus, the present assay may be considered as another behavioral tool to measure impulsivity in animal disease models, especially in the context of ADHD.

• Journal of Korea Water Resources Association
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• v.47 no.5
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• pp.491-500
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• 2014

To estimate the severity of streamflow drought, this study introduced the concept of streamflow drought index based on threshold level method and Seomjingang Dam inflow was applied. Threshold levels used in this study are fixed, monthly and daily threshold, The $1^{st}{\sim}3^{rd}$ analysis results of annual drought, the severe hydrological droughts were occurred in 1984, 1988 and 1995 and the drought lasted for a long time. Annual compared to extreme values of total water deficit and duration, the drought occurred in 1984, 1988, 1995 and 2001 was serious level. In the results of study, because a fixed threshold level is not reflect seasonal variability, at least the threshold under seasonal level was required. Threshold levels determined by the monthly and daily were appropriate. The proposed methodology in this study can be used to forecast low-flow and determine reservoirs capacity.

• Horticultural Science & Technology
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• v.33 no.5
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• pp.625-632
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• 2015

Drought is a severe abiotic stress that affects global crop production. A drought model was created for 'Toyonoka' Fragaria ${\times}$ ananassa, and the effects of drought stress on contents of proline, sugars, and antioxidant enzyme activities were investigated. Strawberry transplants with identical growth were chosen for the experiments and the randomized design included four replications (10 plants per block). The experimental sets differed in the moisture level of the culture medium relative to the range of moisture content as follows: control, 70-85%; mild drought stress, 50-60%; moderate drought stress, 40-50%; and severe drought stress, 30-40%. Drought stress was imposed by limiting irrigation. Plants were sampled and physiological parameters w ere measured on 0, 2, 4, 6, 8, and 10 days after the commencement of droughts tress. The water potential of strawberry leaves decreased in the plants under mild, moderate, and severe stress during the course of the water stress treatment and exhibited a significant difference from the control. Strawberry leaves subjected to drought stress had higher accumulation of proline, sugars, and malondialdehyde, and higher activities of superoxide dismutase, peroxidase, and catalase than leaves of control plants. Malondialdehyde levels increased in parallel with the severity and duration of drought stress. By contrast, antioxidant enzyme activity displayed dynamic responses to drought stress, first increasing and subsequently decreasing as the severity and duration of drought stress increased. These results suggest that strawberry plants respond to drought stress by altering the activities of antioxidant enzymes and the levels of osmotically active metabolites. These biochemical response changes may confer adaptation to drought stress and improve the capacity of plants to withstand water-deficit conditions.