• Journal of the Korean earth science society
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• v.38 no.7
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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.

• Proceedings of the Korean Biophysical Society Conference
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• 1996.07a
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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)

• Proceedings of the Korean Biophysical Society Conference
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• 1999.06a
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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)

• Proceedings of the KSRS Conference
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• v.2
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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.

• Proceedings of the Korean Biophysical Society Conference
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• 2003.06a
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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.

• Proceedings of the Korean Biophysical Society Conference
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• 1997.07a
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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)

• Proceedings of the Korean Biophysical Society Conference
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• 2003.06a
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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.

• Korean journal of applied entomology
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• v.56 no.1
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• pp.1-18
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• 2017

Temperature-dependent development model is an essential component for forecasting models of insect pests as well as for insect population models. This study reviewed the nonlinear models which explain the relationship between temperature and development rate of insects. In the present study, the types of models were classified largely into empirical and biophysical model, and the groups were subdivided into subgroups according to the similarity of mathematical equations or the connection with original idea. Empirical models that apply analytical functions describing the suitable shape of development curve were subdivided into multiple subgroups as Stinner-based types, Logan-based types, performance models and Beta distribution types. Biophysical models based on enzyme kinetic reaction were grouped as monophyletic group leading to Eyring-model, SM-model, SS-mode, and SSI-model. Finally, we described the historical development and characteristics of non-linear development models and discussed the availability of models.

• Proceedings of the Korean Biophysical Society Conference
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• 1998.06a
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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)

• Proceedings of the Korean Biophysical Society Conference
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• 1998.06a
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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)