• Journal of the Korean Society of Child Welfare
• /
• no.56
• /
• pp.1-32
• /
• 2016

The present study examined the mediating effects of parent-child stress on the relationship between perceived neighborhood disorder and problem behaviors. The research hypotheses were based on Pearlin's(1999) stress process model and findings from previous literature. The data from the $4^{th}$-wave of the Korea Youth Panel Survey (KYPS; a panel survey of $8^{th}$-grade students) were analyzed to identify the relationships between the study variables. The sample included 2,301 adolescents (16 to 18 years old). Findings showed that parent-child stress partially mediated the relationship between perceived neighborhood disorder and problem behaviors in adolescents. As adolescents perceived more neighborhood disorder, they were more likely to experience anxiety/depression and aggression. In addition, greater neighborhood disorder were found to be associated with the higher levels of the parent-child stress. Furthermore, when controlling for perceived neighborhood disorder, the higher levels of the parent-child stress were found to be associated with the higher levels of anxiety/depression and aggression. The Sobel test and bootstrapping results showed that parent-child stress partially mediates the relationship between perceived neighborhood disorder and anxiety/depression, as well as the relationship between perceived neighborhood disorder and aggression. Based on the results, we discussed social welfare implications of the study findings to prevent adolescent problem behavior as well as the limitations of the study.

• Korean Journal of Heritage: History & Science
• /
• v.50 no.4
• /
• pp.38-63
• /
• 2017

This study sets out to investigate the installation of royal kilns and its impact on local kilns, taking note of celadon vase with inlaid cloud pattern in Joseon Dynasty. For that purpose, it determined the kilns and period to produce celadon vases with inlaid cloud pattern, and compared them with the pattern, design, and deformity of the celadon vases produced in the royal kilns in the 15th centuries. The celadon vase with inlaid cloud pattern was superior in quality than the porcelain for tribute ware manufactured together in Jeolla Province before the installation of royal kilns. And then a majority of sagijangs at local kiln had difficult time securing enough supply of manpower and resources, and discontinued manufacturing the celadon vase with inlaid cloud pattern. En revanche, celadon vases with inlaid cloud pattern produced from specially fixed royal kilns reflected the local sagijang's skill. Local kilns were strongly influenced by the installation of royal kilns. Those could not freely use high-quality white clay, limited to the market. Besides, most of the skillful sagijangs were assigned to royal kilns. Celadon vases with inlaid cloud pattern can be used as evidence to show that the manufacturing technique was transferred from local kilns to the royal kilns as well as to show that their production in royal kilns soon became stabilized.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.30 no.2
• /
• pp.194-199
• /
• 2024

Accidents due to aircraft fuel defects rank in the top 13 of the 34 accident types described by CAST-ICAO Common Taxonomy Team(CICTT). Aircraft accidents occur because of the inflow of moisture or pollutants depending on the distribution process and storage environment. To confirm the change in physical properties of the aircraft oil stored for a long time, we stored JET A-1 aircraft oil in a metal can to observe the change after six months. We confirmed that the aircraft oil stored for a long time satisfied the quality standards, and the stability of the fuel oil was high. However, in scenarios in which aircraft oil is stored separately on ships, onshore storage facilities, oil fields, etc., owing to the nature of missions, such as in marine police aircraft, the inflow of moisture or pollutants may likely occur due to changes in the internal and external environment. In addition, pollutants can be analyzed using existing tests and distillation properties, but for moisture, domestic and international standards and domestic laws determine the moisture separation ability of aircraft oil through the water separation index, but the moisture content is not analyzed. Therefore, aviation safety must be secured by adding quality control standards for moisture content and performing revisions to uniformize domestic and international standards and laws.

• Korean Journal of Environment and Ecology
• /
• v.32 no.5
• /
• pp.478-485
• /
• 2018

With the total population of 3,356 worldwide as of 2016, the black-faced spoonbill (Platalea minor) is designated as "endangered (EN)" species by IUCN. About 70% of population breeds on the uninhabited islands near the west coast of Korea and wintering area is Taiwan, China, Hong Kong, etc. However, there is few detail research in Korea and East Asia on black-faced spoonbill's long range migration and its habitat when migrating southward. We studied black-faced spoonbill's migration route, distribution, stopover, wintering sites, and timing of migration movements using a wild-tracker (WT-200, GPS-Mobile phone based telemetry, KoEco). We caught the black-faced spoonbills in the breeding sites (Gugi island, Bi island, Sangyeobawi, Chilsan island) in Korea in late June 2014. We attached the wild-tracker to 10 juvenile black-faced spoonbills. The tracking showed that the black-faced spoonbills started southward migration between late October and early November. The traveling distance to wintering site was maximum at 1,820 km, minimum at 746 km, the average at 1,201km. The maximum daily traveling distance was 1,479 km with an average of 782 km. The average days it took from breeding site to wintering site was 10 days (SD=10.7). The shortest duration was 2 days, and the longest duration was 34 days. Most individuals used 2-3 stopover sites between the breeding sites to the wintering sites and stayed almost 1-2 days (maximum 31 days). Stopover sites were wetlands such as rivers, streams, reservoir, and mud flat. The wintering sites were coastal areas (five individuals) in China, inland (one individual) in China, Taiwan (three individuals), and Japan (one individual). In conclusion, it is necessary to preserve the stopover sites and wintering site of the black-faced spoonbills through consultation and protection policy between countries and establish the systematic preservation measures and activity plans through continued moniting and additional studies.

• Journal of Plant Biology
• /
• v.36 no.4
• /
• pp.345-355
• /
• 1993

Anatomical study of the secondary xylem in Araliaceous plants, induding 7 genera and 11 species grown in Korea, was carried out to elucidate the relationship among genera in the family. Wood of Hedera has difbse porous and shows ulmiform pattern of angular vessels, simple perforation plate, and alternate pitting. In addition, its ray is homogeneous type II with only procumbent ray cell. Ring porous wood of Dendropanax shows ulmiform of angular vessels, simple perforation plate, alternate pitting, and heterogeneous type II ray, which has sometimes horizontal secretory cavity. Fatsia has diffuse porous wood, which shows ulmiform of angular vessels, scalariform perforation plate (3-9 bars), scalariform pitting, spiral thickening in the lateral wall of vessel, and heterogeneous type II ray with sheath cells. Kalopanax has ring porous wood, which shows ulmiform of circular vessels, simple perforation plate and alternate pitting, and heterogeneous type II ray. While K pictum appears tylose with septum, K pictum var. maximowczii appears tylose without septum. Echinopanax shows ring porous wood, ulmiform of angular vessels, simple perforation plate, scalariform pitting, and tylose with septum. And the ray of Echinopanax is paedomorphic type I composed of only upright cells. Acanthopanax genus is composed of diffuse porous wood, ulmiform of angular vessels, simple perforation plate and alternate pitting. In this genus, A. sessiliflorus has heterogeneous type II ray, apotracheal axial parenchyma and tylose with septum. A. senticosus appears paedomorphic type I with only upright cells, and tylose with septum. A. koreanum and A. sieboldianum have heterogeneous type II ray but have not tylose. Aralia is composed of ring porous wood, ulmiform of circular vessels, simple perforation plate, alternate pitting, heterogeneous type II ray, and tylose contained both septum and reticulate. On the basis of arrangement, shape, length and diameter of vessel element, the angle of end wall to vessel axis, and ray type, the line of specialization in these genera is as follow: from Fatsia, the most primitive, to the most highly specialized Aralia, throughout Hedera, Acanthopanax, Echinopanax, Dendropanax, and Kalopanax by turns. turns.

• Journal of Korean Society of Forest Science
• /
• v.80 no.2
• /
• pp.162-176
• /
• 1991

For the purpose of contributing to wild birds protection and propagation, distribution characteristics and ecological breeding habitats were surveyed in Mt. Chiri from September, 1986 to December, 1989 by the use of the nestboxes installed in four study sites by the altitude. The results were as follows ; 1. During the study period, observed birds were 2,403 individuals belong to 59 species, especially, at the 1,400m above altitude the rare species, Falco tinnunculus and the protecting bird species such as Ninox scutulata, Strix aluco and Prunella collaris were observed. 2. In the inhabitation structure of birds by the altitude, Fringilla montfringilla was the highest dominance (41.33%) among the inhabitated birds in the surveyed area. 3. Phasianus colchicus and Streptopelia orientalis which were mainly inhabited in hilly area were observed until the altitude of 900m. 4. The 92.5% of nest boxes was mainly used by the small birds, Parus spp. and Sitta europaea. These species preferred the nest boxes installed at the edge or along the mountaineering path, because they could get food and water easily from those places. 5. The utilization rate of the nest boxes was showed 86% at 500m, 96% at 900m, 98% at 1,400m and 90% at 1,700m above the altitude, respectively. 6. The breeding rate of birds in the nest boxes was showed from 6% to 46% by altitude. Parus varius was the highest breeding species in the surveyed area. These birds inhabited above 500m laid eggs from 15th, April to 22th, May(n=22), but those above 1,700m laid eggs from 28th, April to 27th, May(n=13), that 13 days were delayed at high altitude. 7. Food items of the chicks of the 5 species collected by the collar method were animal matters ; 91.3% of the food was forest insects such as Phalera asiimilis and Pleuroptya batteata except 8.7% of spiders.

• The Korean Journal of Pesticide Science
• /
• v.20 no.1
• /
• pp.72-81
• /
• 2016

Feeding behaviors of the pear psylla, Cacopsylla pyricola, and their changing feeding behaviors were recorded and analyzed with an electrical penetration graph (EPG) analysis against 5 insecticides. And their mortality against insecticides were carried out in the laboratory. General feeding behavior patterns of C. pyricola were changed by insecticide treatments. Especially, the type and frequency of waveforms differently occurred depending on a sort of insecticides treated. Total duration of transition to waveform PE1 and phloem ingestion (waveform PE2) were significantly different between treatment and non-treatment of insecticides. When 5 different insecticides were treated on pear leaves, difference of feeding patterns were recorded. In case of treatment of benfuracarb, total duration of non-probes (waveform Np) was appeared higher than any other insecticide. However, when flonicamid and deltamethrin were treatment, total duration of stylet penetration (waveform PA) and xylem ingestion (waveform PG) were appeared higher than other insecticide, respectively. As results feeding behaviour of C. pyricola after treated insecticides with time-based consumed rate of C. pyricola, the rate of non-probe (waveform Np) was longer than start penetration (waveform PA), penetration and ingestion in parenchyma cells (waveform PC1+PC2), ingestion at phloem (waveform PD+PE1+PE2) and xylem (waveform PG). As result of direct spray treatment to C. pyricola, mortality of C. pyricola against imidacloprid was higher than any other insecticide on 24 hours after treatment. However, all of insecticides showed 100% mortality of after 48 hours. On the other hand, when 5 insecticides sprayed on the pear leaves and then C. pyricola located on the treated leaves, benfuracarb showed the most toxicity against C. pyricola among insecticides. These result was consistent with the EPG results that showed relatively longer total duration time of waveform Np (non-probes) by benfuracarb treatment.

• Journal of Korean Society of Forest Science
• /
• v.101 no.4
• /
• pp.613-618
• /
• 2012

The 5-year-old seedlings and emblings which regenerated from somatic embryos were compared to the height, DBH, foliar characteristics, content of chlorophyll (chlorophyll a, b and total chlorophyll), carotenoid and leaf microstructure in Liriodendron tulipifera. In comparison of height and DBH (diameter at breast height), no significant differences were found in height (seedling, 3.8 m; embling, 3.87 m) and DBH (seedling, 12.09 cm; embling, 12.53 cm). The emblings and seedlings were similar in values of length (seedling, 108.11 mm, embling, 113.59 mm), width (seedling, 149.1 mm; embling, 167.71 mm), surface area (seedling, $119.92mm^2$; embling, $164.43mm^2$), fresh weight (seedling, 2.1 g; embling, 2.62 g) of leaf, and length (seedling, 81.49 mm; embling, 98.41 mm) and thickness (seedling, 1.66 mm; embling, 1.98 mm) of petiole. In case of chlorophyll content in the leaves, the chlorophyll a (seedlings, $11.2{\mu}g/g$; emblings, $13.2{\mu}g/g$), b (seedlings, $4.8{\mu}g/g$; emblings, $5.4{\mu}g/g$) and total content were higher in emblings ($930.2{\mu}g/g$) than seedlings ($800.1{\mu}g/g$), however, content of carotenoid (seedlings, $260.3{\mu}g/g$; embling, $265.2{\mu}g/g$) showed similar in both plants. Leaves of emblings had a similar pattern of histological structure (palisade or sponge parenchyma) to that of seedlings leaves. Therefore, the results showed that there were no remarkable growth differences when compared with 5-year-emblings and seedlings of yellow poplar.

• Journal of Animal Science and Technology
• /
• v.49 no.6
• /
• pp.819-828
• /
• 2007

Two experiments were conducted to observe the effects of direct fed microbials on metabolic characteristics in sheep and milking performance in dairy cows. A metabolic trial with four ruminally cannulated sheep(60±6kg) was conducted in a 4×4 Latin square design to investigate the supplementation effects of Saccharomyces cerevisiae, Clostridium butyricum or mixed microbes of S. cerevisiae and C. butyricum on ruminal fermentation characteristics and whole tract digestibility. Sheep were fed 1.25 kg of total mixed ration(TMR, DM basis) supplemented with S. cerevisiae (2.5g/day), C. butyricum (1.0g/day) or its mixture(S. cerevisiae 1.25g/day+C. butyricum 1g/day), twice daily in an equal volume. But control sheep were fed only TMR. A feeding trial with 28 lactating Holstein cattle was also conducted for 12 weeks to investigate the effects of the same microbial supplements as for the metabolic trial on milking performance. The cows were fed the TMR(control), and fed S. cerevisiae(50g/day), C. butyricum(15g/day) or its mixture (S. cerevisiae 25g/day + C. butyricum 7.5g/day) with upper layer dressing method. Total VFA concentration and the digestibility of whole digestive tract in the sheep increased by supplementation of S. cerevisiae, C. butyricum or their combined microbials compare to control group. The proportion of propionic acid at 1h(P<0.039) and 3h(P<0.022) decreased by supplementation of S. cerevisiae while tended to increase acetic acid proportion at the same times. Daily dry matter intake(DMI) was not influenced by the microbial treatments, but milk yield(P<0.031) and feed efficiency(milk yield/DMI, P<0.043) were higher for the cow received C. butyricum than those for other treatments. The milk fat content was higher (P<0.085) when cows fed S. cerevisiae(4.11%) than that fed the control (4.08%), the diets with C. butyricum (3.85%) and the microbial mixture. Based on the results obtained from the current experiments, supplementation of C. butyricum or mixture with S. cerevisiae might be increased milk fat content and milk productivity of lactating daily cows. (Key words:Saccharomyces cerevisiae, Clostridium butyricum, Fermentation characteristics,

• Horticultural Science & Technology
• /
• v.18 no.3
• /
• pp.353-359
• /
• 2000

'Yumyeong' is one of the most popular peach varieties in Korea. This study was conducted to monitor the developments of cells and tissues, and the changes in sugar contents during fruit growth and development. At bloom, there were two rows of vascular tissues, and the number and the position of internal vascular bundles were consistent during the fruit growth, however, the number of vascular tissues were increased and the distribution was irregular in the flesh tissues. The tissues between the inner integument and the internal vascular bundles showed different development characteristics from other parenchyma cells which were consisted of small and dense cells containing tannins. Such observation suggested that the stone of peach was consisted of inner epidermis and cells in the internal vascular tissues. The outer epidermis consisted of single layer cells at bloom differrentiated into 1-2 layers by horizontal cell divisions on 14 days after full bloom. On 30 days after full bloom, the epidermis was consisted of 5-6 layers by vertical cell divisions. The cell layers consisting the outer epidermis were gradually decreased to 1-2 layers at maturity. The observations on the changes in the epidermis confirmed that some of the cells consisting the hypodermis of peach fruit were originated from the cells of outer epidermis. Tylosis was observed from 35 days after full bloom and the size and number of tylosis were increased until full fruit maturity. The sucrose content showed the tendency of sharp increase from 50 days to 120 days after full bloom then decrease slightly. After when stone hardening ended, other solids showed a gradual decrease tendency from 80 days after full bloom.