• The Korean Journal of Ecology
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• v.8 no.2
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• pp.99-107
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• 1985

Photosynthetically Active Radiation (PAR) affects the growth of plants as well as their photosynthetic rates. A mathematical model for intercepted solar radiation on the tilted leaf with any azimuth angle was established and the leaf orientation in which receives the maximum solar radiation was determined each month, during the growing season, and for an year. PAR was maximized at the leaf elevation of 50。~60。 in the winter, at that of 20。~40。. On the whole the leaves of tilt angle 0。~40。 received much radiation comparing with those of other tilt angles. The theoretical tendencies were compared with the distribution of leaf orientation measused practically. The average leaf elevation of maple tree was 17.0。$\pm$12.0。, and that of ginkgo was 29.8。$\pm$16.0。. Several results from other literatures support our suggestion that cumulative effevct of the relationships between surface normal vector and a vector pointing in the direction of the radiation determine the leaf orientation.

• Korean Journal of Environmental Biology
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• v.21 no.4
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• pp.384-391
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• 2003

The induction of chromosome aberrations in Hordeum vulgare germs after irradiation is studied for the dose range of 10 to 1,000 mGy. The relationship between the frequency of aberrant cells and the absorbed dose is shown to be non -linear and has a dose-independent plateau within the range of 56-467 mGy where the level of cytogenetic damage is statistically significantly distinguished from the spontaneous level. The comparison of the goodness of the experimental data fitting with mathematical models of different complexities, using the most common quantitative criteria, demonstrates the benefit of the piecewise linear model over the linear and polynomial ones in approximating the cytogenetical disturbance frequency. The results of our study support the conclusion about indirect mechanism of chromosome aberrations induced by low doses or dose rates mutagenesis.

• Molecules and Cells
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• v.25 no.3
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• pp.397-406
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• 2008

Computational modeling of signal transduction is currently attracting much attention as it can promote the understanding of complex signal transduction mechanisms. Although several mathematical models have been used to examine signaling pathways, little attention has been given to crosstalk mechanisms. In this study, an attempt was made to develop a computational model for the pathways involving growth-factor-mediated mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3'-kinase/protein kinase B (PI3K/Akt). In addition, the dynamics of the protein activities were analyzed based on a set of kinetic data. The simulation approach integrates the information on several levels and predicts systems behavior. The in-silico analysis conducted revealed that the Raf and Akt pathways act independently.

• Interdisciplinary Bio Central
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• v.3 no.2
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• pp.8.1-8.6
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• 2011

Background: Thanks to the development of the mathematical/statistical reverse engineering and the high-throughput measuring biotechnology, lots of biologically meaningful genegene interaction networks have been revealed. Steady-state analysis of these systems provides an important clue to understand and to predict the systematic behaviours of the biological system. However, modeling such a complex and large-scale system is one of the challenging difficulties in systems biology. Results: We introduce a new stochastic modeling approach that can describe gene regulatory mechanisms by dividing two (DNA and protein) layers. Simple queuing system is employed to explain the DNA layer and the protein layer is modeled using G-networks which enable us to account for the post-translational protein interactions. Our method is applied to a transcription repression system and an active protein degradation system. The steady-state results suggest that the active protein degradation system is more sensitive but the transcription repression system might be more reliable than the transcription repression system. Conclusions: Our two layer stochastic model successfully describes the long-run behaviour of gene regulatory networks which consist of various mRNA/protein processes. The analytic solution of the G-networks enables us to extend our model to a large-scale system. A more reliable modeling approach could be achieved by cooperating with a real experimental study in synthetic biology.

• Korean Journal of Environmental Biology
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• v.20 no.4
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• pp.277-286
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• 2002

An increase in the overall biological effect under the combined action of ionizing radiation with another inactivating agent can be explained in two ways. One is the supposition that synergism may attribute to a reduced cellular capacity of damn-ge repair after the combined action. The other is the hypothesis that synergism may be related to an additional lethal or potentially lethal damage that arises from the interaction of sublesions induced by both agents. These sublesions ave considered to be in-effective when each agent is applied separately. Based on this hypothesis, a simple mathematical model was established. The model can predict the greatest value of the synergistic effect, and the dependence of synergy on the intensity of agents applied, as well. This paper deals with the model validation and the peculiarity of simultaneous action of various factors with radiation on biological systems such as bacteriophage, bacterial spores, yeast and mammalian cells. The common rules of the synergism aye as follows. (1) For any constant rate of exposure, the synergy can be observed only within a certain temperature range. The temperature range which synergistically increases the effects of radiation is shifted to the lower temperature fer thermosensitive objects. Inside this range, there is a specific temperature that maximizes the synergistic effect. (2) A decrease in the exposure rate results in a decrease of this specific temperature to achieve the greatest synergy and vice versa. For a constant temperature at which the irradiation occurs, synergy can be observed within a certain dose rate range. Inside this range an optimal intensity of the physical agent may be indicated, which maximizes the synergy. As the exposure temperature reduces, the optimal intensity decreases and vice versa. (3) The recovery rate after combined action is decelerated due to an increased number of irreversible damages. The probability of recovery is independent of the exposure temperature for yeast cells irradiated with ionizing or UV radiation. Chemical inhibitors of cell recovery act through the formation of irreversible damage but not via damaging the recovery process itself.

• The Mathematical Education
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• v.58 no.3
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• pp.383-401
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• 2019

This study started with the idea that it is necessary to focus on common concepts and ideas among the subjects when conducting integrated education in high school. This is a preliminary study for developing materials that can be taught in mathematics in the context of already learning scientific concepts in high school. For this purpose, Mendel 's law of genetics was studied among the contents of biological subjects which are known to have relatively little connection with mathematics. The more common links between the two subjects are, the better, in order to integrate math and other subjects and develop materials for teaching. Therefore, in this study, we investigated not only the probability domain but also the concept of statistical domain. We have been wondering if there is a more abundant idea to connect between 'Mendel's law' and 'probability and statistics'. Through these anxieties, we could find that concepts such as 'likely equality' and 'permutation and combination' including 'a large number of laws' can be a link between two subjects. Based on this, we were able to develop class materials that correspond to classes. This study is expected to help with research related to development of integrated education support materials, focusing on mathematics.

• Journal of Science Education
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• v.48 no.1
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• pp.15-30
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• 2024

This study aimed to analyze students' cognitive levels and the cognitive demands of mathematical concepts related to science to understand why students struggle to comprehend scientific concepts and tend to avoid learning them. Initially, the mathematics and science curricula of the 2015 revised curriculum were examined to extract learning elements related to mathematics within middle school science content. The Curriculum Analysis Taxonomy (CAT) was then employed to analyze the cognitive levels required by the learning content. In the domain of chemistry, among a total of 20 learning elements related to mathematics, 12 required an understanding at the level of initial formal manipulation (3A), while 3 necessitated comprehension at the level of later formal manipulation (3B). It was noted that cognitive logic types such as proportional reasoning, mathematical manipulation, and measurement skills were prominently employed in elements corresponding to both 3A and 3B. As for biology, out of 7 learning elements related to mathematics, 3 required an understanding at the level of initial formal manipulation (3A), and 2 necessitated comprehension at the level of later formal manipulation (3B). Elements corresponding to both 3A and 3B in biology predominantly involved correlational logic, indicating a somewhat different cognitive challenge compared to the domain of chemistry. Considering that the average percentage of middle school students capable of formal thinking, as analyzed through the GALT short form, was 12.1% for the first year, 16.6% for the second year, and 29.3% for the third year, it can be concluded that the cognitive demands of mathematics-related chemistry and biology learning content are relatively high compared to students' cognitive levels.

• The Korean Journal of Ecology
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• v.7 no.3
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• pp.109-118
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• 1983

Near future dynamics of water qualities (nutrient concentration) of the Han River was predicted, based on a mathematical model representing the relationship between the nutrient concentration in th river wagter and environmental factors (population density, land-use types, rock compositions and nutrient accumulation) in the basin. The population density and land-use types were forecasted to change distinctly in the downstream area, especially in Seoul City area in 1985~1990 whereas any environmental factor was not expected to change its level significantly in both upstream and middle reaches areas. It was indicated by the model that the nutrients concentration in the up- and mid-streams would keep its level in future as it was, but it would increase drastially in the downstream area. For the preservation of the water qualities in the downstream at least to keep its level as it was in 1980, practical countermeasures were proposed, based on the assessment of the contribution of each environmental factor to the water qualities.

• Geomechanics and Engineering
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• v.16 no.2
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• pp.141-150
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• 2018

In this current work a quasi 3D "trigonometric shear deformation theory" is proposed and discussed for the dynamic of thick orthotropic plates. Contrary to the classical "higher order shear deformation theories" (HSDT) and the "first shear deformation theory" (FSDT), the constructed theory utilizes a new displacement field which includes "undetermined integral terms" and presents only three "variables". In this model the axial displacement utilizes sinusoidal mathematical function in terms of z coordinate to introduce the shear strain impact. The cosine mathematical function in terms of z coordinate is employed in vertical displacement to introduce the impact of transverse "normal deformation". The motion equations of the model are found via the concept of virtual work. Numerical results found for frequency of "flexural mode", mode of shear and mode of thickness stretch impact of dynamic of simply supported "orthotropic" structures are compared and verified with those of other HSDTs and method of elasticity wherever considered.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.8
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• pp.4897-4902
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• 2013

Here we assessed the effectiveness of cervical cancer screening using data from the Hiroshima Prefecture Cancer Registry regarding patient age at the start of screening and differences in screening intervals. A screening model was created to calculate the health status in relation to prognosis following cervical cancer screening and its influence on life expectancy. Epidemiological data on the mortality rate of cervical cancer by age groups and mortality rates from the Hiroshima Prefecture Cancer Registry were used for the model projections. Our results showed that life expectancy when screening rate was 100% compared with 0% was extended by approximately 1 month. Furthermore, when the incidence of cervical cancer was 0% compared with the screening rate was 100%, life expectancy was extended by a maximum of 3 months. Moreover, among individuals affected by cervical c ancer, a difference of 13 years in life expectancy was calculated between screened and unscreened groups.