건답직파재배에서 요소 비료 시용시 벼의 질소 이용과 손실

이변우 서울대학교 농업개발연구소 1999 농업생명과학연구 Vol.3 No.-

The objectives of this study were to evaluate the loss and recovery of urea nitrogen applied at sowing as basal nitrogen and topdressed shortly after flooding at four- to six-leaf stage of rice, and the effectiveness of nitrogen split application method, a nitrification inhibitor, DCD (dicyandiamide), and a slow release fertilizer, latex-coated urea(LCU) on the nitrogen economy and yield performance of rice sown directly on dry paddy field. Urea applied at seeding was lost almost completely during dry paddy period of 20 to 30 days before permanent flooding. Plant recovery of nitrogen applied at sowing was only 2.5 to 3.2% with 91 to 96% loss during dry paddy period until 4-leaf stage, showing little year to year variation. Nitrogen loss due to ammonia volatilization covered only 1 to 11%, and the rest substantial part of loss appeared to be due to leaching and denitrification. Both leaching and denitification were important mechanisms of nitrogen loss during dry paddy period before permanent flooding. Urea topdressed shortly after flooding at four-leaf stage was utilized 8 to 40% by plant with 15 to 50% loss within 10 days after fertilization, being much less in N loss compared to urea applied at sowing. Nitrogen topdressed at this stage was lost primarily due to leaching at very early stage of fertilization because of very high rate of water percolation. Ammonia volatilization loss was very low, accounting only for below 2% of applied nitrogen. The data suggested that urea fertilization at sowing as basal fertilizer should be avoided or reduced to a minimum amount and the nitrogen alloted to basal fertilizer in conventional dry-seeding rice culture rather be supplemented to the topdressing shortly after permanent flooding at four to six-leaf stage of rice for improving nitrogen fertilization efficiency and rice yield. DCD increased slightly the plant recovery of fertilizer nitrogend and rice yield. However, such a degree of improvement might be achieved by other means of fertilization practice without chemical.

출엽 및 최종엽수 추정에 의한 벼 발육 예측모델 개발

이변우 서울대학교 농업개발연구소 2001 농업생명과학연구 Vol.5 No.-

Under the constant daylength the final number of rrice leaves on the main culm(FNL) was constant regardless of temperature in rice variety 'Kwanganbyeo'. Leaf appearance rate(LAR) increased with rising temperature and decreased with phenological development. LAR was well fitted to the following model; dL/dt=(T_i-T_0)·(-a^-1·b^(1/c)·c·(a-L)^((c-1)/c)·L^((c+1)/c)) where dL/dt is LAR, t_i and T_0 are daily mean and threshold temperature, L is the number of leaves appeared, and a, b, and c are constants that were estimated as 41.8, 1098.38, and -0.9273 in Kwanganbyeo, respectively. FNL shoed very close relationship with the average daylength during photosensitive period(PSP) of six-leaf stage to panicle initiation, being well fitted to the following rational function(R^2=0.98); FNK=(a+bD)/(1+cD), where D is daylength and a, b, and c are the constants that wee estimated as 14.694, -0.992, and -0.068 in Kwanganbyeo, respectively. The rice phenology model, which was composed of the two component models for LAR and FNL, predicted developmental stage very accurately. The differences between the observed and predicted days to heading was less than two days in the sowing date field experiments in 1999 and 2000 of which data were not used for the model construction.

벼의 한계질소농도 결정 및 군락반사율을 이용한 질소영양상태 추정 연구

이변우 서울대학교 농업개발연구소 2000 농업생명과학연구 Vol.4 No.-

Critical nitrogen concentration(Nc) which is defined as the minimum nitrogen concentration to maintain the maximum growth rate at any time was investigated for rice plant. Based on Nc, nitrogen nutrition index(NNI) was calculated as its ratio to actual nitrogen concentration to examine the relationship with yield and yield components. In addition, investigated were the feasibilities to apply canopy reflectance measurements to diagnosing the nitrogen nutrition status nondestructively. Shoot critical nitrogen concentrations had no differences between rice varieties, Hwasungbyeo and Dasanbyeo, having the relationship with shoot dry weight(DW) as Nc=5.26DW-4.138(R2=0.966). This Nc dilution curve can be applied only in case that DW is greater than 1 to 1.5t/ha. For the early growth stage with DW less than 1 to 1.5t/ha, Nc should be determined with further detailed experiments. Nitrogen nutrition index(NNI), which is calculated as the ratio of Nc to actual N concentration, represented nitrogen nutrition status of rice very well. Showing the close relationship with rice yield and its components. Visible light reflectance had no great variations as LAI increases above 2. While near infra red(NIR) reflectance increased with LAI increase. Visible light reflectance decreased but NIR reflectance changed little with the increased nitrogen application levels. In cas of LAI less than 2, it was difficult to estimate canopy characteristics such as plant nitrogen concentration and NNI by canopy reflectance as the background reflectance of paddy soil and water contributed too much to canopy reflectance(ρ). Whereas, plant nitrogen concentration and NNI of rice canopy with LAI above 2 had very significant correlations with visible band reflectances, RVI, NDVI and so forth. Especially, RVIgreen(□) and NDVIgreen(□) showed the close linear regression relationship with NNI which had coefficients of determination of R2=0.802 and R2=0.845, respectively, indicating that these vegetation indexes could be used effectively to estimate NNI nondestructively. However, further studies to get rid of background effects on canopy reflectance are needed for the effective diagnosis of nitrogen nutrition status with canopy reflection measurements even in early growth stage with LAI below 2.

Kainic Acid로 유발된 경련이 흰쥐 대뇌피질의 Vasoactive Instestinal Polypeptide 신경세포에 미치는 영향에 관한 면역조직화학적 연구

허영범,변우현,이원규,김정혜,안희경 대한해부학회 1995 Anatomy & Cell Biology Vol.28 No.2

멀칭에 따른 지온변화 모델의 작성 및 토양온도의 추정

최일선,이변우 한국농림기상학회 1999 한국농림기상학회지 Vol.1 No.2

A numerical model using soil surface energy balance and soil heat flow equations to estimate mulched soil temperature was developed. The required inputs data include weather data, such as global solar radiation, air temperature, wind speed, atmospheric water vapor pressure, the optical properties of mulching material, and soil physical properties. The observed average soil temperature at 50 cm depth was used as the initial value of soil temperature at each depth. Soil temperature was simulated starting at 0 hour at an interval of 10 minutes. The model reliably described the variation of soil temperature with time progress and soil depth. The correlation between the estimated and measured temperature yielded coefficient values of 0.961, 0.966 for 5cm and 10cm depth of the bare soil, respectively, 0.969, 0.965 for the paper mulched soil, and 0.915, 0.938 for the black polyethylene film mulched soil. The percentages of absolute differences less than 2℃ between soil temperatures measured and simulated at 10 minute interval were 97.4% and 98.5% for 5 cm and 10cm for the bare soil, respectively, and 95.8% and 97.4% for the paper mulched soil, and 70.1% and 92.5% for the polyethylene film mulched soil. The results indicated that the model was able to predict the soil temperature fairly well under mulched condition. However, in the night time, the model performance was a little poor as compared with day time due to the difficulty of accurate determination of the atmospheric long wave radiation.

Three Newly Recorded Species of the Genus Olethreutes (Lepidoptera, Tortricidae) from North Korea

Bong-Kyu Byun,Bong-Woo Lee,Ha Yong Choi,Seung Jin Roh 한국응용곤충학회 2012 한국응용곤충학회 학술대회논문집 Vol.2012 No.10

In North Korea, the Tortricidae has been poorly studied until Byun et al. (1998) reviewed 350 species from Korea, including 63 species of Tortricinae and 40 species of Olethreutinae. Then Razowski (1999) presented a checklist of 358 species of Tortricidae from Korea, including 176 species of the North Korean Tortricidae with mostly based on the avaialble materials in Poland and previous literatures. Later, a serial studies on the family Tortricdae of North Korea with the material deposited in the Hungarian Natural History Museum provided several additional data for the North Korean tortricid fauna (Byun 2009; Byun 2011a; Byun 2011b; Byun 2011c; Byun et al. 2007) During the course of the study on the Tortricidae of North Korea deposited in Hungarian Natural History Museum, the author found three species of Olethreutes for the first time from North Korea. Of them, Olethreutes aviana Falkovitsh is also newly reported to the Korean peninsula. The aim of the present study is to report the three species of Olethreutes as new to North Korean fauna. In the present study, three species of the genus Olethreutes: O. aviana Falkovitsh, O. obovata (Walsingham), and O. orthocosma (Meyrick), based on the material deposited in the Hungarian Natural History Museum, are reported for the first time from North Korea. Among them, O. aviana Falkovitsh is recorded as new to the Korean peninsula. Photographs of the adults and genitalia of the species are presented.

Differential effects of blood insulin and HbA1c on cerebral amyloid burden and neurodegeneration in nondiabetic cognitively normal older adults

Byun, Min Soo,Kim, Hyun Jung,Yi, Dahyun,Choi, Hyo Jung,Baek, Hyewon,Lee, Jun Ho,Choe, Young Min,Sohn, Bo Kyung,Lee, Jun-Young,Lee, Younghwa,Ko, Hyunwoong,Kim, Yu Kyeong,Lee, Yun-Sang,Sohn, Chul-Ho,Woo PERGAMON PRESS LTD 2017 NEUROBIOLOGY OF AGING Vol. No.

<P><B>Abstract</B></P> <P>We tested the hypothesis that lower insulin or higher glycated hemoglobin (HbA1c) levels in blood are associated with increased cerebral beta amyloid (Aβ) deposition and neurodegeneration in nondiabetic cognitively normal (CN) older adults. A total of 205 nondiabetic CN older adults underwent comprehensive clinical assessment, [<SUP>11</SUP>C]Pittsburgh compound B (PiB)-positron emission tomography (PET), [<SUP>18</SUP>F]fluorodeoxyglucose-PET, magnetic resonance imaging, and blood sampling for fasting insulin and HbA1c measurement. Lower blood insulin was significantly associated with increased Aβ positivity rates and decreased cerebral glucose metabolism in the AD-signature region. In contrast, higher HbA1c levels were not associated with Aβ positivity rates but were significantly associated with higher rates of having neurodegeneration in the AD-signature regions. Our results suggest different roles of insulin and HbA1c in AD pathogenesis, in that decreased blood insulin below optimal levels may contribute to increasing cerebral Aβ deposition and neurodegeneration whereas impaired glycemic control may aggravate neurodegeneration through a nonamyloid mechanism in nondiabetic CN older adults.</P>

Effect of Recycled Paper Mulch on Yield of Fall-grown Potato

Lee, Byun-Woo,Cui, Ri-Xian,Lee, Suk-Ha The Korean Society of Crop Science 2002 Korean journal of crop science Vol.47 No.1

High temperature during sprout emergence period of potato (Solanum tuberosum L.) is a major limitation to the yield of fall-grown potato in Korea. To explore the possibility of improving the yield of fall-grown potato through recycled paper mulching, the changes of soil environment and the growth and yield of potato cv. Daeji as affected by three mulching treatments of non-mulched control, recycled paper mulching (RPM), and black polyethylene film-mulching (BPFM) were examined over two fall seasons at Suwon, Korea. The mulching materials were a recycled mulch paper with 110 g/$m^2$ and a thickness of 0.1 mm, which was manufactured from old corrugated containers for this experiment and a commercial black polyethylene film with a thickness of 0.01mm. On an average throughout the growing period, the soil temperature with RPM at the 5-cm depth was lower by 0.4-1.1$^{\circ}C$ than that of the control. The maximum temperature during daytime in RPM was lowered by approximately 1 to 5$^{\circ}C$ according to the weather condition during emergence period, the difference being great on a fine day. The soil temperature with BPFM was much higher than the control. The effect of the mulching treatments diminished as the canopy became developed. The mulching treatments were more advantageous than the control in the conservation of soil water. Moreover, RPM and BPFM efficiently suppressed the occurrence of weeds until the potato harvest. RPM improved the emergence significantly due to lower soil temperature, whereas BPFM showed much poorer emergence than the control. Growth after emergence and yield were significantly higher in RPM than in the control and BPFM. It was concluded that the significantly improved yield in RPM compared to that in the control was mainly due to the improvement of the sprout emergence and tuber growth accompanied by lower soil temperature and better conservation of soil water.

Reduced P300 amplitude during a visuospatial attention task in idiopathic rapid eye movement sleep behavior disorder

Byun, Jung-Ick,Lee, Byeong Uk,Kim, Minah,Sunwoo, Jun-Sang,Lim, Jung-Ah,Moon, Jangsup,Lee, Soon-Tae,Jung, Keun-Hwa,Chu, Kon,Kim, Man-Ho,Jeong, Min Hee,Cha, Kwang Su,Choi, Jeong Woo,Kim, Kyung Hwan,Lee, Elsevier 2017 SLEEP MEDICINE Vol.38 No.-

<P><B>Abstract</B></P> <P><B>Objectives</B></P> <P>Idiopathic rapid eye movement sleep behavior disorder (IRBD) patients are prone to cognitive deficits, which include attention, executive, and visuospatial dysfunctions. Even patients with normal cognition may exhibit subclinical electrophysiological dysfunction. This study aimed to evaluate visuospatial attention processing in IRBD patients with normal cognition and to compare their findings with those of age- and sex-matched healthy controls.</P> <P><B>Methods</B></P> <P>We recorded event-related potentials (ERPs) and performance measures during a variant of the Posner task in 14 IRBD patients and 14 control subjects. Behavioral data and the mean P300 amplitude were compared between groups.</P> <P><B>Results</B></P> <P>No group difference was found for reaction time or accuracy, but a significant group effect was observed for the P300 amplitude. IRBD patients had reduced P300 amplitude (μV) than controls in both valid (IRBD: 0.53 ± 1.05 vs Controls: 1.61 ± 0.95; p = 0.008) and invalid (IRBD: 0.74 ± 0.99 vs Controls: 1.73 ± 0.86; p = 0.009) conditions. The P300 amplitude was correlated with Montreal cognitive assessment (MOCA) scores (r = 0.424, p = 0.024).</P> <P><B>Conclusion</B></P> <P>Reduced P300 amplitude during the Posner task provides electrophysiological evidence for subclinical visuospatial attention deficits in cognitively normal IRBD patients. The results of this study imply that cortical dysfunction is already present in patients with IRBD in their early disease stage.</P> <P><B>Highlights</B></P> <P> <UL> <LI> IRBD with normal cognition had reduced P300 amplitude during Posner task. </LI> <LI> Reduced P300 in IRBD was independent of age, sex, depression, and autonomic function. </LI> <LI> The P300 amplitude correlated with MOCA scores. </LI> <LI> Cortical dysfunction may be present in early stage of IRBD. </LI> </UL> </P>

High Performance Poly-Si Thin Film Transistors Fabricated by a Simple Crystallization Method Using Ni-Silicide Seeds

Byun, Chang Woo,Son, Se Wan,Lee, Yong Woo,Kang, Hyun Mo,Park, Seol Ah,Lim, Woo Chang,Li, Tao,Joo, Seung Ki The Electrochemical Society 2011 Journal of the Electrochemical Society Vol.158 No.11