Assessment of Agricultural Drought Considering the Hydrological Cycle and Crop Phenology in the Korean Peninsula

Hydrological changes attributable to global warming increase the severity and frequency of droughts, which in turn affect agriculture. Hence, we proposed the Standardized Agricultural Drought Index (SADI), which is a new drought index specialized for agriculture and crops, and evaluated current and expected droughts in the Korean Peninsula. The SADI applies crop phenology to the hydrological cycle, which is a basic element that assesses drought. The SADI of rice and maize was calculated using representative hydrological variables (precipitation, evapotranspiration, and runoff) of the crop growing season. In order to evaluate the effectiveness of SADI, the three-month Standardized Precipitation Index, which is a representative drought index, and rainfed crop yield were estimated together. The performance evaluation of SADI showed that the correlation between rainfed crop yield and SADI was very high compared with that of existing drought index. The results of the assessment of drought over the past three decades provided a good indication of a major drought period and differentiated the results for crops and regions. The results of two future scenarios showed common drought risks in the western plains of North Korea. Successfully validated SADIs could be effectively applied to agricultural drought assessments in light of future climate change, and would be a good example of the water-food nexus approach

Assessment of Agricultural Drought Considering the Hydrological Cycle and Crop Phenology in the Korean Peninsula

Hydrological changes attributable to global warming increase the severity and frequency of droughts, which in turn affect agriculture. Hence, we proposed the Standardized Agricultural Drought Index (SADI), which is a new drought index specialized for agriculture and crops, and evaluated current and expected droughts in the Korean Peninsula. The SADI applies crop phenology to the hydrological cycle, which is a basic element that assesses drought. The SADI of rice and maize was calculated using representative hydrological variables (precipitation, evapotranspiration, and runoff) of the crop growing season. In order to evaluate the effectiveness of SADI, the three-month Standardized Precipitation Index, which is a representative drought index, and rainfed crop yield were estimated together. The performance evaluation of SADI showed that the correlation between rainfed crop yield and SADI was very high compared with that of existing drought index. The results of the assessment of drought over the past three decades provided a good indication of a major drought period and differentiated the results for crops and regions. The results of two future scenarios showed common drought risks in the western plains of North Korea. Successfully validated SADIs could be effectively applied to agricultural drought assessments in light of future climate change, and would be a good example of the water-food nexus approach

Assessment of the modulation degrees of intensity-modulated radiation therapy plans

Background To evaluate the modulation indices (MIs) for predicting the plan delivery accuracies of intensity-modulated radiation therapy (IMRT) plans. Methods A total of 100 dynamic IMRT plans that used TrueBeam STx and 102 dynamic IMRT plans that used Trilogy were selected. For each plan, various MIs were calculated, which included the modulation complexity score (MCS), plan-averaged beam area (PA), plan-averaged beam irregularity (PI), plan-averaged beam modulation (PM), MI quantifying multi-leaf collimator (MLC) speeds (MIs), MI quantifying MLC acceleration (MIa), and MI quantifying MLC acceleration and segment aperture irregularity (MIc,IMRT). To determine plan delivery accuracy, global gamma passing rates, MLC errors of log files, and dose-volumetric parameter differences between original and log file-reconstructed IMRT plans were obtained. To assess the ability of each MI for predicting plan delivery accuracy, Spearmans rank correlation coefficients (rs) between MIs and plan delivery accuracy measures were calculated. Results PI showed moderately strong correlations with gamma passing rates in MapCHECK2 measurements of both TrueBeam STx and Trilogy (rs = − 0.591 with p <  0.001 and − 0.427 with p <  0.001 to with gamma criterion of 2%/2 mm, respectively). For ArcCHECK measurements, PI also showed moderately strong correlations with the gamma passing rates in the ArcCHECK measurements of TrueBeam STx and Trilogy (rs = − 0.545 with p <  0.001 and rs = − 0.581 with p <  0.001 with gamma criterion of 2%/2 mm, respectively). The PI showed the second strongest correlation with MLC errors in both TrueBeam STx and Trilogy (rs = 0.861 with p <  0.001 and rs = 0.767 with p <  0.001, respectively). In general, the PI showed moderately strong correlations with every plan delivery accuracy measure. Conclusions The PI showed moderately strong correlations with every plan delivery accuracy measure and therefore is a useful predictor of IMRT delivery accuracy.This work was supported by a National Research Foundation of Korea (NRF) grant from the Korea government (MSIP). (No.2017M2A2A7A02020639, No.2017M2A2A7A02020640, No.2017M2A2A7A02020641, No.2017M2A2A7A02020643)

Modeling the Fate and Transport of Malathion in the Pagsanjan-Lumban Basin, Philippines

Exposure to highly toxic pesticides could potentially cause cancer and disrupt the development of vital systems. Monitoring activities were performed to assess the level of contamination; however, these were costly, laborious, and short-term leading to insufficient monitoring data. However, the performance of the existing Soil and Water Assessment Tool (SWAT model) can be restricted by its two-phase partitioning approach, which is inadequate when it comes to simulating pesticides with limited dataset. This study developed a modified SWAT pesticide model to address these challenges. The modified model considered the three-phase partitioning model that classifies the pesticide into three forms: dissolved, particle-bound, and dissolved organic carbon (DOC)-associated pesticide. The addition of DOC-associated pesticide particles increases the scope of the pesticide model by also considering the adherence of pesticides to the organic carbon in the soil. The modified SWAT and original SWAT pesticide model was applied to the Pagsanjan-Lumban (PL) basin, a highly agricultural region. Malathion was chosen as the target pesticide since it is commonly used in the basin. The pesticide models simulated the fate and transport of malathion in the PL basin and showed the temporal pattern of selected subbasins. The sensitivity analyses revealed that application efficiency and settling velocity were the most sensitive parameters for the original and modified SWAT model, respectively. Degradation of particulate-phase malathion were also significant to both models. The rate of determination (R2) and Nash-Sutcliffe efficiency (NSE) values showed that the modified model (R2 = 0.52; NSE = 0.36) gave a slightly better performance compared to the original (R2 = 0.39; NSE = 0.18). Results from this study will be able to aid the government and private agriculture sectors to have an in-depth understanding in managing pesticide usage in agricultural watersheds

Successful treatment of type I endoleak of common iliac artery with balloon expandable stent (Palmaz XL stent) during endovascular aneurysm repair

Type 1 endoleak of common iliac artery (type Ib endoleak) should be treated during endovascular aneurysm repair (EVAR). An 86-year-old female was diagnosed with abdominal aortic aneurysm measuring 6.6 cm in diameter and right internal iliac artery aneurysm measuring 4.0 cm in diameter. She underwent EVAR after right internal iliac artery embolization. There was type Ib endoleak, which was repaired by balloon-expandable stent, Palmaz XL stent (Cordis). We report successful treatment of type Ib endoleak with Palmaz XL stent, which may be considered as an alternative option for type Ib endoleak after EVAR

Callus induction and in vitro mass culture of adventitious roots from leaf segment explants of Dendropanax morbifera Lev.

Dendropanax morbifera Lev. is a unique species and natively found in Korea and distributed in the South regions, such as Jeju, Goheung, and Wando. In this study, tissue culture system for native D. morbifera was developed. The callus from native D. morbifera leaves was cultured on Woody Plant Media (WPM) supplemented with 30 g L–1 of sucrose, with addition of 2.4-D and BA [(0.5, 1.0, 2.0) mg L–1 ], separately and mixed. After 5 wk of culture, the highest induction of callus was obtained from 0.5 mg L–1 of 2.4-D mixed with 2.0 mg L–1 of BA. Adventitious root formation on different media (MS, WPM, B5) with various auxins (IBA, IAA, and NAA) and different concentration [(0, 1, 3, 5) mg L–1 ] were tested. After 8 wk of culture, WPM showed better induction of adventitious root. The highest induction of adventitious root was obtained on 3.0 mg L–1 IBA. Root growth was best in WPM liquid medium with 3.0 mg L–1 of IBA and 30 g L–1 of sucrose. The same formulation with modified ½ WPM was successfully established in vitro adventitious roots culture in 18-L bioreactor system. This study also proposed as the mass production technique of adventitious roots from native D. morbifera