• Korean Journal of Environment and Ecology
• /
• v.25 no.3
• /
• pp.295-301
• /
• 2011

In order to investigate the geographical variation of Glycine max distributed in southern area of Korean peninsula, 19 local strains(Goseng, Pyeongchang, Ganghwa, Pocheon, Geumsan, Seocheon, Jincheon, Danyang, Tongyeong, Sancheong, Gumneung, Wolseong, Woolneung, Wando, Naju, Gochang, Jangsu, Jeju, Bukjeju), which located from $33^{\circ}15'N$ to $38^{\circ}11'N$, were selected according to their latitudes and geographical distances. The seeds of these strains were collected and their contents of mannose and galactose were investigated. Mannose contents in the seeds were variable in the range between the highest 12.207mg/g(Gochang) and the lowest 6.648mg/g(Geumsan). The contents of galactose were represented remarkable differences from 9.967mg/g(Danyang) to 16.949mg/g(Bukjeju) also. The local strains were classified into 4 variation types such as the inland type I(Wolseong, Jangsu, Danyang), the coastal type I(Gochang, Naju, Jeju, Goseng, Woolneung, Bukjeju, Ganghwa, Seocheon, Tongyeong), the inland type II(Geumsan, Pocheon, Pyeongchang) and the coastal type II(Wando, Jincheon) and 2 strange strains(Gumneung, Sancheong) according to the geographical climatic type and the ratio of mannose/galactose, which indicate the hardness of seeds in Leguminosae, ranged from 0.63 to 0.78. The variation types are very significant genecologically as an evidence for microevolution related to speciation in cultivated plants.

• Journal of the korean society of oceanography
• /
• v.33 no.3
• /
• pp.80-89
• /
• 1998

Three cores were taken from the northwest Pacific Ocean (Shikoku Basin) to determine the accumulation rates of both biogenic and terrigeneous fractions since the last penultimate interglacial period. The sediment is characterized by large amounts of terrigenous materials with low biogenic fractions and intermittent volcanic-ash layers, suggesting a hemipelagic origin. Composition of major elements shows no significant differences among sites. Relatively small variation of TiO$_2$/Al$_2$O$_3$ ratios with respect to SiO$_2$ content is the strong evidence for the common origin of terrigenous materials. The fraction of biogenic carbonates varies from near 0% in ash layers to about 35%, with a gradual increase toward the south (St. 4 through St. 6 to St. 20). However, carbonate contents show step-wise increasing tendency from St. 4 through St. 6 to St. 20, which suggests a southward increase of carbonate production. The color reflectance indicates that the sediment of the southern sites contains relatively higher amounts of biogenic carbonates. The mass accumulation rate of terrigenous fractions during the glacial period was 2-3 times higher than that of interglacial period. This enhanced mass accumulation rate of terrigenous materials was concomitant with the high accumulation rate of biogenic fractions. The total sediment accumulation rate is considered as the most important factor controlling mass accumulation rates of the biogenic and terrigenous materials. The enhanced sediment accumulation during the glacial periods is interpreted as a consequence of climate-induced change in the supply of eolian dust from the Asian continent. Enhanced wind strength during the glacial time may have increased transportation of terrigenous materials to the ocean. Thus, variation of sediment accumulation is highly linked with climatic variations.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.41 no.6
• /
• pp.493-504
• /
• 2008

In the seas around the Korean Peninsula, the seasonal cycle of zooplankton related to North Pacific regime shifts was investigated to understand the reaction of the ecosystem to climate change using long-term data on zooplankton biomass (1965-2000) and the abundance of four major zooplankton groups: copepods, amphipods, chaetognaths, and euphausiids (1978-2000). In general, the zooplankton biomass showed a large peak in spring and a small peak in autumnin Korean waters, but there was a slight difference in the peak time depending on the location and the period before and after the North Pacific regime shift. The zooplankton biomass showed conspicuous seasonal peaks in R-III (1990-2000) compared to R-I (1965-1976) and R-II (1977-1988), and the seasonal peak shifted from the autumn in R-II to the spring in R-III. The peak of copepods and euphausiids in abundance was from April to June, while chaetognaths peaked from August to October. We postulate that the time lag between the peaks for copepods and chaetognaths results from the predator-prey relationship. The regime shift in 1989 did not alter the seasonal cycle of the four major zooplankton groups, although it enhanced their production. The seasonal peaks of the four major zooplankton groups did not shift, while the seasonal peaks of the zooplankton biomass did shift. This was not only becausethe zooplankton biomass included other mesozooplankton groups but also because the abundance of the four major zooplankton groups increased significantly in spring.

• Journal of the Korean Geotechnical Society
• /
• v.19 no.1
• /
• pp.41-49
• /
• 2003

Rainfall-induced landslides in a weathered granite soil slope usually happen on shallow slip surfaces above the groundwater table. The pore-water pressure of soil above the groundwater table is usually negative. This negative pore-water pressure (or matric suction) has been found to make a large contribution to the slope stability. Therefore, the variation of in-situ matric suction profiles with time elapse in a soil slope should be understood. In this study, a field measurement program was carried out from June to August, 2001 in order to monitor in-situ matric suctions and volumetric water contents in a weathered granite soil slope. Finite-element transient seepage analyses are also conducted using SEEP/W. The influence of climatic conditions on the variation of in-situ matric suctions could be found to decrease rapidly with the change of depth. It could be found that decrement of matric suction induced by precipitation is affected not only by the amount and duration of rainfalls but also by the initial matric suction just prior to rainstorms. The soil-water characteristic from the field monitoring tends toward the wetting path of SWCC obtained from the laboratory test.

• Atmosphere
• /
• v.27 no.1
• /
• pp.79-91
• /
• 2017

It is imperative to understand the characteristics of atmospheric circulation patterns under the climate system due to its impact on climatic factors. Thus this study focused on analyzing the impact of the atmospheric circulation on the relationship between precipitation and temperature regionally. Here we used monthly gridded observational data (i.e., CRU-TS3.2, NOAA-20CR V2c) and HadGEM2-AO climate model by RCP8.5, for the period of 1960~1999 and 2060~2099. The experiment results indicated that the negative relationship was presented over East Asia and Europe during summer. On the other hand, at around Korea (i.e. EA1: $31^{\circ}N{\sim}38^{\circ}N$, $126^{\circ}E{\sim}140^{\circ}E$) and Northwestern Europe (i.e. EU1: $48^{\circ}N{\sim}55^{\circ}N$, $0^{\circ}E{\sim}16^{\circ}E$) in winter, strong positive relationship dominate due to warm moist advection come from ocean related to intensity variation of the East Asian winter monsoon (EAWM) and North Atlantic Oscillation (NAO), respectively. It was found that values of positive relation in EA1 and EU1 at the end of the 21st century is regionally greater than at the end of 20th century during winter since magnitude of variation of the EAWM and NAO is projected to be greater in the future as result of simulation with RCP 8.5. Future summer, the negative correlations are weakened in EA1 region while strengthened in EU1 region. For better understanding of correlations with respect to RCP scenarios, a further study is required.

• Journal of Animal Science and Technology
• /
• v.58 no.6
• /
• pp.22.1-22.15
• /
• 2016

Background: Dietary manipulation is a common practice to mitigate gaseous emission from livestock production facilities, and the variation of fat level in the diet has shown great influence on ruminal volatile fatty acids (VFA) and enteric methane generation. The changes in dietary fat levels influence rumen chemistry that could modify manure nutrient composition along with odor and gaseous emissions from manure management facilities. Methods: A field experiment was carried out on beef cattle feedlots to investigate the effect of four levels of dietary fat concentrations (3 to 5.5 %) on the manure composition and gaseous emissions (methane-$CH_4$, nitrous oxide-$N_2O$, carbon dioxide-$CO_2$ and hydrogen sulfide-$H_2S$) from the feedlot pen surface. The experiment was carried out over a 5-month period from June to October during North Dakota's summer-fall climatic condition. Air and manure sampling was conducted five times at a 20-30 day intervals. Results: Overall, this research indicated that fat levels in diet have no or little effect on the nutrient composition of manure and gaseous emission from the pens with cattle fed with different diet. Though significant variation of gaseous emission and manure composition were observed between different sampling periods, no effect of high fat diet was observed on manure composition and gaseous emission. Conclusions: It can be concluded that addition of fat to animal diet may not have any impact on gaseous emission and manure compositions.

• Geomechanics and Engineering
• /
• v.19 no.1
• /
• pp.1-9
• /
• 2019

Shallow failures occur frequently in both engineered and natural slopes in expansive soils. Rainfall infiltration is the most predominant triggering factor that contributes to slope failures in both expansive soils and clayey soils. However, slope failures in expansive soils have some distinct characteristics in comparison to slopes in conventional clayey soils. They typically undergo shallow failures with gentle sliding retrogression characteristics. The shallow sliding mass near the slope surface is typically in a state of unsaturated condition and will exhibit significant volume changes with increasing water content during rainfall periods. Many other properties or characteristics change such as the shear strength, matric suction including stress distribution change with respect to depth and time. All these parameters have a significant contribution to the expansive soil slopes instability and are difficult to take into consideration in slope stability analysis using traditional slope stability analysis methods based on principles of saturated soil mechanics. In this paper, commercial software VADOSE/W that can account for climatic factors is used to predict variation of matric suction with respect to time for an expansive soil cut slope in China, which is reported in the literature. The variation of factor of safety with respect to time for this slope is computed using SLOPE/W by taking account of shear strength reduction associated with loss of matric suction extending state-of-the art understanding of the mechanics of unsaturated soils.

• Asian Journal of Atmospheric Environment
• /
• v.6 no.2
• /
• pp.127-135
• /
• 2012

Urbanization has led to a reduction in green spaces and thus transformed the spatial pattern of urban land use. An increase in air temperature directly affects forest vegetation, phenology, and biodiversity in urban areas. In this paper, we analyze the changing land use patterns and urban heat distribution (UHD) in Seoul on the basis of a spatial assessment. It is necessary to monitor and assess the functions of green spaces in order to understand the changes in the green space. In addition, we estimated the influence of green space on urban temperature using Landsat 7 Enhanced Thematic Mapper Plus (ETM+) imagery and climatic data. Results of the assessment showed that UHD differences cause differences in temperature variation and the spatial extent of temperature reducing effects due to urban green space. The ratio of urban heat area to green space cooling area increases rapidly with increasing distance from a green space boundary. This shows that urban green space plays an important role for mitigating urban heating in central areas. This study demonstrated the importance of green space by characterizing the spatiotemporal variations in temperature associated with urban green spaces.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.16
• /
• pp.6889-6894
• /
• 2015

Gastric cancer (GC) is the fifth most common cancer in the world, with a wide variation in incidence rates across different geographical areas. In Iran GC is the most common cancer in males and it is reported to be the third most prevalent after breast and colorectal in females. A geographical information system (GIS) allows investigation of the geographical distribution of diseases. The purpose of the present study was to explore the relationship between gastric cancer and effective climatic factors using GIS. The dispersion distribution and the relationship between environmental factors effective on cancer were measured using Arc GIS. Of all cases, 672 (73.8%) were in males with a sex ratio of 3 to1. The highest incidence by cities was seen in Namin with 137.5 per 100,000. The results of this study showed that the distribution of GC around the Sabalan volcanic mountain was significantly higher than other places in the same province. These results can be considered as a window to future comprehensive research on gastric cancer.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2005.05b
• /
• pp.894-899
• /
• 2005

Since 1970s, rapid industrialization brought urbanization nationwide. In this paper, precipitation changes have been studied for Seoul and other 6 major cities using 31 years of precipitation data from 1973 to 2003. In addition, to consider the other global climatic impacts including El Nino events, precipitation change comparisons have been made between urban and rural areas. Thus, statistical analysis methods have been adopted for annual precipitation, summer precipitation, 1 hour annual maxima series, and 24 hour annual maxima series for both urban and rural areas. The result yields that annual and summer precipitation have been increased in urban areas compare to rural areas.