This study investigated the effects of exposure frequency, depth of processing, and activity repetition types on vocabulary learning. In total, 78 South Korean fifth-grade students were divided into four conditions. Students in each condition were asked to read a passage with four of the eight target words (exposure: four times) and the other four words (exposure: once) for three days, and to perform the vocabulary activities assigned to each condition. According to the results, exposure frequency and activity repetition type had significant effects on vocabulary learning. Activity repetition type also had a significant interaction effect with exposure frequency and depth of processing. Notably, presenting a word 12 times (4x3) in reading intervals had a more positive impact on vocabulary learning than presenting it three times (1x3), particularly when different vocabulary activities were repeated. Meanwhile, when the same activity was repeated, an activity with a higher depth of processing was more effective for vocabulary learning.
The present study examined the receptive and productive knowledge of collocations of second language (L2) and heritage speakers of Korean and also investigated the influence of phrasal frequency, exposure to Korean, and phonological short-term memory (PSTM). Seventeen L2 learners and 14 heritage speakers of Korean were tested on 30 Korean noun-verb collocations, which varied in phrasal frequency, using an acceptability judgment task and a collocation completion test. The results showed that both L2 and heritage speakers demonstrated considerable receptive knowledge of Korean collocations while productive knowledge was more limited for both groups. The mixed-effects modelling results of four independent variables of interest (i.e., phrasal frequency, exposure via media, academic use, and PSTM) showed that phrasal frequency was the only significant predictor of receptive knowledge of collocations for both L2 and heritage speakers; none of the four factors had a significant impact on productive knowledge of collocations for either group. These data are discussed in relation to previous studies on collocation development of L2 learners and heritage speakers.
The objective of this study was to assess RF-EMF exposure levels in indoor daycare centers in a Metropolitan city. RF-EMF measurements were collected and surveyed from 50 volunteer daycare centers in the Korea between October 2013 and October 2014. Through our research, it was found that the main exposure source for indoor daycare centers is the frequency bands for TV and Radio broadcasting (FM: 88.1~107.9 MHz), mobile phone (869~894 MHz, 1840~1870 MHz, 1885~2170 MHz), wireless LAN and home electronics, etc., including TRS, Wireless Data Communication. The RF-EMF exposure levels for all daycare centers were far below the recommended standards of EMF Guideline Korea and international reference levels proposed by ICNIRP (International Commission on Non-Ionizing Radiation Protection). However, in terms of long term health effects some uncertainty exists, and thus minimizing exposure may reduce this uncertainty. The data we collected will be useful data for determining RF-EMF management and risk communication at daycare centers.
We divided the sample into four groups by temperature regimes and comparing the Lethal effect after exposure to high room temperatures for 50~58 days. After inoculating Cnidium officinale Makino with Tribolium castaneum Herbst, the storage insects of medicinal herbs, was 20 respectively. The results of treating cut Cninium officinale Makino are listed below. Survival rate of group A by exposure of 5 times at 35~36.5℃ is less than 7.5%. Survival rate of group C by exposure of 5 times at 35.5~39.5℃ and group D by exposure of 23day at 37~44℃ is less than 2.5%. Especially in the case of group D, we found that complete eradication of the insect is difficult despite exposure high temperature for a long time. Also most of the grinded Cninium officinale Makino has the same patten but group B by relatively treated low temperature has a significant difference in mortality. Insect mortality in cut Cninium officinale Makino by exposure at 35℃ and 39.5℃ is 7.5% and the insect mortality in grinded Cninium officinale Makino by exposure at 39. 5℃ is only 75%. The reason is estimated that heat conduction of grinded Cninium officinale Makino is slow and it was less shocked by heat because The final core temperature of medicinal herbs is relatively low about 0.5~2℃. This means that storage insect(Tribolium castaneum Herbst) can be suppressed at mid-high temperature if it is to be treated more than 50 days without problem of quality deterioration of medicinal herbs that can be caused by high temperature.
The objective of this study was to evaluate Extremely Low Frequency Magnetic Fields (ELF-MFs) exposure level of housewives and the relation of residential environments with ELF-MFs exposure level in home. ELF-MFs measurements were performed for 58 housewives include 31 working women. Twenty-four hours personal MF exposure levels of housewives were slightly higher than working women as an arithmetic mean. However the median of 24 hours personal exposure levels for working women were significantly higher than housewives (p<0.05). The median of personal exposure levels due to the activity at home, working women were higher than housewives significantly (p<0.05). As a results of correlation of residential environments, such as their living environments, total income, type of water supply pipes, and distance from power line with ELF-MFs exposure level in home was different from the type of residence (p<0.05). This study could be informed as guidance for ELF-MFs exposure analysis in residential environment.