• Journal of Aquaculture
• /
• v.16 no.2
• /
• pp.94-98
• /
• 2003

Effect of temperature (5, 10, 15, 18, 21$^{\circ}C$) on pre-and post-embryonic development of the sea urchin Strongylocentrotus intermedius was studied. The egg, which measured 122.5 ${\mu}{\textrm}{m}$, became globular. At 18$^{\circ}C$, it attained 4 celled stage at 3 hours after fertilization, hatched after 15 hours, 4-armed larval stage after 3 days and 8- armed larval stage after 20 days. The relationships between temperature (WT) and time (1, hour) required for each of the selected developmental stages are: Hatching: 1/t=0.0036WT+0.0088 Pyramid: 1/t=0.0014Wl-0.0016 4- armed: 1/t=0.0009WT-0.0020 6- armed: 1/t=0.0004WT-0.0005 8-armed : 1/t=0.0002WT+0.0002 Biological minimum temperature for the egg and larval development is calculated as 1.61$^{\circ}C$.

• Journal of Ecology and Environment
• /
• v.38 no.1
• /
• pp.95-107
• /
• 2015

Because an ecological community consists of diverse species that vary nonlinearly with environmental variability, its dynamics are complex and difficult to analyze. To investigate temporal variations of benthic macroinvertebrate community, we used the community data that were collected at the sampling site in Baenae Stream near Busan, Korea, which is a clean stream with minimum pollution, from July 2006 to July 2013. First, we used a self-organizing map (SOM) to heuristically derive the states that characterizes the biotic condition of the benthic macroinvertebrate communities in forms of time series data. Next, we applied the hidden Markov model (HMM) to fine-tune the states objectively and to obtain the transition probabilities between the states and the emission probabilities that show the connection of the states with observable events such as the number of species, the diversity measured by Shannon entropy, and the biological water quality index (BMWP). While the number of species apparently addressed the state of the community, the diversity reflected the state changes after the HMM training along with seasonal variations in cyclic manners. The BMWP showed clear characterization of events that correspond to the different states based on the emission probabilities. The environmental factors such as temperature and precipitation also indicated the seasonal and cyclic changes according to the HMM. Though the usage of the HMM alone can guarantee the convergence of the training or the precision of the derived states based on field data in this study, the derivation of the states by the SOM that followed the fine-tuning by the HMM well elucidated the states of the community and could serve as an alternative reference system to reveal the ecological structures in stream communities.

• Korean Journal of Food Science and Technology
• /
• v.21 no.3
• /
• pp.446-452
• /
• 1989

The pigment of the Korean cockscomb flower, a betacyanin, was evaluated for its stability in terms of temperature, pH, and its behavior upon exposure to water, light, and air. The pigment was the most stable at pH 4.0, and its activation energy (Ea) for degradation was shown to be 17.55Kcal/mol. In general, sugars protected against color degradation at the concentration of 0.1M. Degradation of this pigment in the presence of food constituents, such as organic acids , metal ions, or antioxidants, at the concentrations normally present in food preparations, can be kept to a minimum by selective adjustment of conditions. This pigment, therefore, has potential value as a food colorant under selected conditions.

• Journal of the korean society of oceanography
• /
• v.32 no.1
• /
• pp.28-37
• /
• 1997

Two marine bivalve shells were collected from the eastern and western coastal regions of Korea, respectively. Stable oxygen and carbon isotope profiles are constructed using the incremental sampling along the axis of maximum growth to provide the continuous ${\delta}^{18}$O and ${\delta}^{13}$C records, which register the physical, biological and chemical properties of seawater where the organisms live. Cycles in the ${\delta}^{18}$O profiles are interpreted as annual along with the identification of annual growth bands; the maximum ${\delta}^{18}$O values correspond with the coldest temperature of seawater whereas the minimum ${\delta}^{18}$O values with the warmest temperature. The primary control on the amplitude of the ${\delta}^{18}$O profiles is seasonal variation of seawater temperature. The offset of the baseline between ${\delta}^{18}$O values of the two specimens is attributed to differences in both temperature and seawater ${\delta}^{18}$O values between two localities. The ${\delta}^{13}$C profiles show the similar seasonality of carbon cycling associated with phytoplankton productivity. The offset in the ${\delta}^{13}$C profiles between two specimens may be, as in the case of oxygen isotope profile, attributed to the different ${\delta}^{13}$C value of the seawater DIC (dissolved inorganic carbon) between the western coast and the eastern coast. Relationships between the shell isotopic composition and the coastal water properties of shell growth are readily interpreted from the ${\delta}^{18}$O-${\delta}^{13}$C pair diagram of the shell isotope data, similar to the use of salinity-${\delta}^{18}$O diagram for identifying water masses. The preliminary stable isotope results of this study suggest that mollusk shell isotope geochemistry may be useful to monitor the properties of water masses in the coastal and inner shelf setting around Korea and improve the interpretation of paleoceanography, provided the fossil mollusks are well preserved.

• Progress in Superconductivity and Cryogenics
• /
• v.15 no.3
• /
• pp.40-48
• /
• 2013

Cryoablation device is a surgical instrument to produce the cooling effect to destroy detrimental biological tissue by utilizing low temperature around 110 K. Usually, this device has the concentrated cooling region, so that it is suitable for concentrated and thick target. Accordingly, it is hard to apply this device for the target which is distributed and thin target. In this study, the design procedure of a closed-loop cryoablation device with multiple J-T expansion part is developed for the treatment of incompetent of great saphenous vein. The developed cyoablation device is designed with the analysis of 1-dimensional (1-D) bio-heat equation. The energy balance is considered to determine the minimum mass flow rate of refrigerant for consecutive flow boiling to develop the uniform cooling temperature. Azeotropic mixed refrigerant R410A and zeotropic mixed refrigerant (MR) of R22 ($CHClF_2$) and R23 ($CHF_3$) are utilized as operating fluids of the developed cryoablation device to form the sufficient temperature and to verify the quality of the inside of cryoablation probe. The experimental results of R410A and the zeotropic MR show the temperature non-uniformity over the range are $244.8K{\pm}2.7K$ and $239.8K{\pm}4.7K$ respectively. The experimental results demonstrate that the probe experiences the consecutive flow boiling over the target range of 200 mm.

• Korean Journal of Environmental Biology
• /
• v.24 no.1 s.61
• /
• pp.60-66
• /
• 2006

This study was carried out to obtain the biological fundamental data for the resources annexation of Crassostrea ariakensis in terms of the effect of temperature and salinity on growth. Water temperature during the sampling period was $3.5\sim26.2^{\circ}C$ and there was a little difference between each sites. Salinity was ranged from 2.6 to 29.5 psu, its maximum in Baealdo and its minimum in Dontak. The fatness index was the higher in Dontak than the other sites. In August, the value was the lowest in 3 sites. Therefore Crassostrea ariakensis is likely to have spawning period June and July. Size values $(mean{\pm}S.D.)$ of shell height was $149.7{\pm}19.8\;mm$ (Baealdo), $148.6{\pm}21.3\;mm$ (Seomjin bridge) and $143.1{\pm}17.6\;mm$ (Dontak), respectively. Relative growth equations among SH, SL, SW, TW and MW of Crassostrea ariakensis were ranged from 0.024 to 0.0471.

• Mycobiology
• /
• v.45 no.4
• /
• pp.240-254
• /
• 2017

Cereal grains are the most important food source for humans. As the global population continues to grow exponentially, the need for the enhanced yield and minimal loss of agricultural crops, mainly cereal grains, is increasing. In general, harvested grains are stored for specific time periods to guarantee their continuous supply throughout the year. During storage, economic losses due to reduction in quality and quantity of grains can become very significant. Grain loss is usually the result of its deterioration due to fungal contamination that can occur from preharvest to postharvest stages. The deleterious fungi can be classified based on predominance at different stages of crop growth and harvest that are affected by environmental factors such as water activity ($a_w$) and eco-physiological requirements. These fungi include species such as those belonging to the genera Aspergillus and Penicillium that can produce mycotoxins harmful to animals and humans. The grain type and condition, environment, and biological factors can also influence the occurrence and predominance of mycotoxigenic fungi in stored grains. The main environmental factors influencing grain fungi and mycotoxins are temperature and $a_w$. This review discusses the effects of temperature and $a_w$ on fungal growth and mycotoxin production in stored grains. The focus is on the occurrence and optimum and minimum growth requirements for grain fungi and mycotoxin production. The environmental influence on aflatoxin production and hypothesized mechanisms of its molecular suppression in response to environmental changes are also discussed. In addition, the use of controlled or modified atmosphere as an environmentally safe alternative to harmful agricultural chemicals is discussed and recommended future research issues are highlighted.

• Korean journal of applied entomology
• /
• v.47 no.2
• /
• pp.163-168
• /
• 2008

Temperature dependent development of Tetranychus. urticae Koch was studied on the leaf of eggplant at 17, 22, 27, 32 and $37^{\circ}C$. T. urticae showed a minimum mortality at $27^{\circ}C$ and it increased at higher or lower temperatures than $27^{\circ}C$. The hatchability was low at 17 and $37^{\circ}C$. The duration of development decreased with increasing temperatures i.e., 5.3d at $37^{\circ}C$ and 25.8d at $17^{\circ}C$. Linear regression analysis of temperature vs. rate of development yielded the higher $r^2{\geq}0.88$ resulting in a good fit of the estimated line in the range of $17{\sim}37^{\circ}C$. Developmental zero temperature was $12.5^{\circ}C$ for the entire immature stage of female and $12.8^{\circ}C$ for that of male. Thermal constants were 80.5 and 74.7 degree days for those of female and male, respectively. Adult life span and oviposition period decreased with increasing temperatures. The number of eggs laid per female peaked at 141.0 eggs at $27^{\circ}C$, while that was a minimum 78.0 eggs at $37^{\circ}C$. Rate of hatchability, ratio of female, and $R_o$ were increased up to $27^{\circ}C$, and than declined thereafter. Intrinsic rate of natural increase (Rm) increased with rising temperatures and showed a maximum 0.5652 at $37^{\circ}C$. Also, ${\lambda}$ increased with increasing temperature. Doubling time (Dt) and generation time (T) decreased with increasing temperature.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.17 no.2
• /
• pp.144-148
• /
• 1988

Differential scanning calorimerty(DSC) was used to study gelatinization phenomena of defatted rice, corn, wheat, potato starch and nondefatted rice and wheat starch at heating rate $5{\sim}15^{\circ}C/min$. Gelatinization temperature of defatted rice and wheat starch indicated $4{\sim}5^{\circ}C$ lower temperature than nondefatted starch. More rapid heating rate resulted in a increasing of the gelatinization enthalpy for various starches. A linear relation was observed between water content, heating rate and gelatinization temperature. From the linear relationship existing between water content and gelatinization enthalpy, minimum water content for the gelatinization were 41, 38, 33 and 30% of rice, potato, wheat and corn starch, respectively.

• Korean journal of applied entomology
• /
• v.61 no.4
• /
• pp.577-590
• /
• 2022

Ostrinia scapulalis is one of important pests in leguminous crops, especially red bean. In order to understand the biological characteristics of the insect, we investigated the effects of temperature on development of each life stage, adult longevity and fecundity of O. scapulalis at eleven constant temperatures of 7, 10, 13, 16, 19, 22, 25, 28, 31, 34, and 36℃. Eggs and larvae successfully developed next life stage at most temperature subjected except 7, 10 and 13℃. The developmental period of egg, larva and pupa decreased as temperature increased. Lower and higher threshold temperature (TL and TH) were calculated by the Lobry-Rosso-Flandrois (LRF) and Sharpe-Schoolfield-Ikemoto (SSI) models. The lower developmental threshold (LDT) and thermal constant (K) from egg hatching to adult emergence of O. scapulalis were estimated by linear regression as 13.5℃ and 384.5DD, respectively. TL and TH from egg hatching to adult emergence using SSI model were 19.4℃ and 39.8℃. Thermal windows, i.e., the range in temperature between the minimum and maximum rate of development, of O. scapulalis was 20.4℃. Adults produced viable eggs at the temperature range between 16℃ and 34℃, and showed a maximum number, ca. 416 offsprings, at 25℃. Adult models including aging rate, age-specific survival rate, age-specific cumulative oviposition, and temperature-dependent fecundity were constructed, using the temperature-dependent adult traits. Temperature-dependent development models and adult oviposition models will be useful components to understand the population dynamics of O. scapulalis and will be expected using a basic data for establishing the strategy of integrated pest management in leguminous crops.