• Title/Summary/Keyword: Biophysical model

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Biophysical Effects Simulated by an Ocean General Circulation Model Coupled with a Biogeochemical Model in the Tropical Pacific

  • Park, Hyo-Jin;Moon, Byung-Kwon;Wie, Jieun;Kim, Ki-Young;Lee, Johan;Byun, Young-Hwa
    • 한국지구과학회지
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    • 제38권7호
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    • pp.469-480
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    • 2017
  • Controversy has surrounded the potential impacts of phytoplankton on the tropical climate, since climate models produce diverse behaviors in terms of the equatorial mean state and El $Ni{\tilde{n}}o$-Southern Oscillation (ENSO) amplitude. We explored biophysical impacts on the tropical ocean temperature using an ocean general circulation model coupled to a biogeochemistry model in which chlorophyll can modify solar attenuation and in turn feed back to ocean physics. Compared with a control model run excluding biophysical processes, our model with biogeochemistry showed that subsurface chlorophyll concentrations led to an increase in sea surface temperature (particularly in the western Pacific) via horizontal accumulation of heat contents. In the central Pacific, however, a mild cold anomaly appeared, accompanying the strengthened westward currents. The magnitude and skewness of ENSO were also modulated by biophysical feedbacks resulting from the chlorophyll affecting El $Ni{\tilde{n}}o$ and La $Ni{\tilde{n}}a$ in an asymmetric way. That is, El $Ni{\tilde{n}}o$ conditions were intensified by the higher contribution of the second baroclinic mode to sea surface temperature anomalies, whereas La $Ni{\tilde{n}}a$ conditions were slightly weakened by the absorption of shortwave radiation by phytoplankton. In our model experiments, the intensification of El $Ni{\tilde{n}}o$ was more dominant than the dampening of La $Ni{\tilde{n}}a$, resulting in the amplification of ENSO and higher skewness.

The Molecular Mechanical Model of DD-Peptidase

  • Lim, Eongjin;Won, Youngdo
    • 한국생물물리학회:학술대회논문집
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    • 한국생물물리학회 1996년도 정기총회 및 학술발표회
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    • pp.22-22
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    • 1996
  • In order to establish the structural requirements for designing new ${\beta}$-lactam antibiotics it is necessary to build the molecular model of a penicillin binding protein. D-alanyl-D-alanine carboxypeptidase/transpeptidase (DD-peptidase) is a good model for PBPs. The X -ray crystallographic structure of DD-peptidase has been reported at the 1.6${\AA}$ resolution. (omitted)

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Interactions of Peptides with Model Membrane Systems Studied by NMR Spectroscopy

  • Kim, Yangmee
    • 한국생물물리학회:학술대회논문집
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    • 한국생물물리학회 1999년도 학술발표회 진행표 및 논문초록
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    • pp.19-19
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    • 1999
  • The functions and the medicinal values of peptides are closely related to their structures. Most of the peptides function in the mediation of the membrane. Biological membrane serves important functions in the binding of peptide to a membrane-embedded receptor.(omitted)

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VALIDITY OF NDVI-BASED BIOPHYSICAL PARAMETERS FOR ECOSYSTEM MODELS

  • Lee, Kyu-Sung;Jang, Ki-Chang;Kim, Tae-Geun;Lee, Seung-Ho;Cho, Hyun-Guk
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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    • pp.543-546
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    • 2006
  • NDVI has been very frequently used to estimate several biophysical parameters that are required for ecosystem models. Leaf area index (LAI), canopy closure, and biomass are among those biophysical parameters that are estimated by empirical relationship with NDVI. However, the type of remote sensing signals (raw DN value, at-sensor radiance, atmospherically corrected reflectance) used can vary the calculation of NDVI. In this study, we tried to attempt to compare the influence of NDVI linked with forest LAI for the watershed-scale ecosystem models to estimate evapotranspiration. Landsat ETM+ data were used to obtain various NDVI values over the study area in central Korea. The NDVI-based LAI and the resultant evapotranspiration estimation were greatly varied by the remote sensing signal applied.

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Linear Dynamic Model of Gene Regulation Network of Yeast Cell Cycle

  • Changno Yoon;Han, Seung-Kee
    • 한국생물물리학회:학술대회논문집
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    • 한국생물물리학회 2003년도 정기총회 및 학술발표회
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    • pp.77-77
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    • 2003
  • Gene expression in a cell is regulated by mutual activations or repressions between genes. Identifying the gene regulation network will be one of the most important research topics in the post genomic era. We propose a linear dynamic model of gene regulation for the yeast cell cycle. A small gene network consisting of about 40 genes is reconstructed from the analysis of micro-array gene expression data of yeast S. cerevisiae published by P. Spellman et al. We show that the network construction is consistent with the result of the hierarchical cluster analysis.

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A Stochastic Model of Voltage-Gated Ion Channel

  • Lee, Kwonmoo;Wokyung Sung;Gabriel Weinreb
    • 한국생물물리학회:학술대회논문집
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    • 한국생물물리학회 1997년도 학술발표회
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    • pp.35-35
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    • 1997
  • We model the voltage-gated cation channel on the basis of stochastic process by taking into account transmembrane movement of S4 group interacting electrostatically with permeant ions. It is assumed that the interaction between the ion and S4 group is repulsive harmonic force and the ionic motion is much faster than that of the S4 group.(omitted)

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Phase Model Analysis of Yeast Glycolytic Oscillation

  • Kim, Won-Sup;Han, Seung-Kee
    • 한국생물물리학회:학술대회논문집
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    • 한국생물물리학회 2003년도 정기총회 및 학술발표회
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    • pp.78-78
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    • 2003
  • The glycolysis is one of the most important metabolic reactions through which the glucose is broken and the released energy is stored in the form of ATP. Rhythmic oscillation of the intracellular ATP is observed as the amount of the influx glucose is small in the yeast. The oscillation is also observed in the population of the yeast cells, which implies that the glycolytic oscillation of the yeasts is synchronous. It is not clear how the synchronous oscillation could be organized among the yeast cells. Although detailed mathematical models are available that show synchronization of the glycolytic oscillation, the stability of the synchronous oscillation is not clear. We introduce a phase model analysis that reduces a higher dimensional mathematical model to a much simpler one dimensional phase model. Then, the stability of the synchronous oscillation is easily determined by the stability of the corresponding fixed solution in the phase model. The effect of perturbation on the oscillatory rhythm is also easily analyzed in the reduced phase model.

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비선형 곤충 온도발육모형의 특성과 발전과정에 대한 고찰 (A Review for Non-linear Models Describing Temperature-dependent Development of Insect Populations: Characteristics and Developmental Process of Models)

  • 김동순;안정준;이준호
    • 한국응용곤충학회지
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    • 제56권1호
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    • pp.1-18
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    • 2017
  • 곤충의 온도발육모형은 해충의 발생예찰모형을 비롯한 개체군모형에서 기본이 되는 요소이다. 본고에서는 곤충의 온도의존적 비선형 발육모형에 대하여 고찰하였다. 모형의 종류를 크게 경험모형과 생물리적 모형으로 구분하였으며, 수식의 유사성 내지 기원에 대한 유연관계에 따라 세분하였다. 발육률 곡선의 형태적 묘사에 적합한 수식을 적용하는 경험모형은 Stinner-계열, Logan-계열, 수행모형, 그리고 베타 분포모형으로 세분화하여 고찰하였다. 촉매반응을 바탕으로 하고 있는 생물리적 모형은 Eyring-모형, SM-모형, SS-모형, SSI-모형으로 이어지는 단계통으로 분류하였다. 본 연구에 포함된 각 모형의 개발과정과 형태적합 특성에 대하여 기술하였다.

Effects of Nonlamellar-Prone Lipids on the ATPase Activity of SecA Bound to Model Membranes

  • Taeho Ahn;Kim, Hyoungman
    • 한국생물물리학회:학술대회논문집
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    • 한국생물물리학회 1998년도 학술발표회
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    • pp.27-27
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    • 1998
  • The effect of nonlamellar-prone lipids, diacylglycerol (DG) and phosphatidylethanolamine (PE), on the ATPase activity of SecA was examined. When Escherichia coli (E. coli) PE of the standard vesicles composed of 60 mol% of this lipid and 40 mol% of dioleoylphosphatidylglycerol (DOPG) is gradually replaced with either dioleoylgylcerol (DOG) or dioeloyl PE(DOPE), the ATPase activity of SecA present together increased appreciably.(omitted)

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Conformational Role of Proline in $\alpha$-Helices

  • Kang, Young-Kee;Kim, Mee-Kyoung
    • 한국생물물리학회:학술대회논문집
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    • 한국생물물리학회 1998년도 학술발표회
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    • pp.22-22
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    • 1998
  • Conformational energy calculations have been carried out for proline-containing alanine-based pentadecapeptides with the sequence Ac-(Ala)/sun n/-Pro-(Ala)$_{m}$-NHMe (n + m = 14), in order to figure out the positional preference of proline in $\alpha$-helices. The conformational energy was computed a sum of the potential energy (ECEPP/3) and the hydration free energy computed by the hydration shell model.(omitted)d)

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