• Title/Summary/Keyword: Difference-in-Differences(DID)

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Differences in Vowel Duration Due to the Underlying Voicing of the Following Coda Stop in Russian and English: Native and Non-native Values

  • Oh, Eun-Jin
    • Speech Sciences
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    • v.13 no.3
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    • pp.19-33
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    • 2006
  • This study explores whether Russian, known to have a process of syllable-final devoicing, reveals differences in vowel duration as a function of the underlying voicing of the coda stop. This paper also examines whether non-native speakers of Russian and English learn typical L2 values in vowel duration. The results indicate that vowels in Russian have a slightly longer mean duration before a voiced stop than before a voiceless stop (a mean difference of 9.52 ms), but in most cases the differences did not exhibit statistical significance. In English the mean difference was 60.05 ms, and the differences were in most cases statistically significant. All native Russian speakers of English produced larger absolute differences in vowel duration for English than for Russian, and all native English speakers of Russian produced smaller absolute differences for Russian than for English. More experienced learners seemed to achieve more native-like values of vowel duration than less experienced learners did, suggesting that learning occurs gradually as the learners gain more experience with the L2.

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Effects of Rapeseed Oil Diet on Serum and Liver Lipid Levels in Rats (유채유 함유사료가 쥐의 혈청 및 간의 지질조성에 미치는 영향)

  • 서은숙;김인숙
    • The Korean Journal of Food And Nutrition
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    • v.7 no.3
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    • pp.192-202
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    • 1994
  • The fatty acid composition of a rapeseed oil being on the market was analyzed and the effect on gain of the body weight and lipid levels in serum and liver tissue of male rats of Sprague-Dawely strain fed the diet containing the rapeseed oil were studied. The fatty acid components of marketed rapeseed oil was oleic acid 29.4%, erucic acid 26.52%, linoleic acid 20.39% and linolenic acid 8.68%. The contents of total lipid in serum W3S Significantly higher in RSO20 group than Contr01 group(P< 0.01) . But that in the liver tissue did 001 show significant differences. The contents of triglyceride in serum was control group 84.14mg/dll, RSO15 group 100.33mg 141 and RSO20 group 122.00mg 141 and showed significant difference between each group, but that in the livertissue did not show significant differences. The contents of phospholipid in serum did not show significant differences. But that in the liver tissue showed significant difference between the control group 8.42mg /g and Rs02o group 7.34mg /g(p<0.001). The contents of total-cholesterol and free-cholesterol in serum and liver tissue of the RSO20 group showed the highest levels compared with control group, but there did not show significant differences. The contents of ester-cholesterol in serum showed significant.

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Thermographic Findings in Craniomandibular Disorders ; Clinical Evaluation (두개하악장애환자의 임상적 평가를 위한 컴퓨터적외선체열검사)

  • Ick-Joo Cho;Jung-Pyo Hong;Sang-Rae Lee
    • Journal of Oral Medicine and Pain
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    • v.20 no.2
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    • pp.477-487
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    • 1995
  • The purpose of this study was to assess the thermographic differences of craniomandibular area between normal individual and patients with craniomandibular disorders and to compare the differences between clinical and thermographical assessment. The author had used 50 subjects as materials for this study, which was divided into 2 groups (first group included 15 healthy subjects and second group included 35 patients) with craiomandibular disorders; 17 subjects had normal disc-condyle relationship, 13 subjects had disc displacement with reduction and 5 subjects had disc displacement without reduction. Agema 870 thermovision(D.I.T.I.) was used to take thermographs with $0.1^{\circ}C$ difference of gradual temperature shift. The results were as follows : 1. Of 34 patients with craniofacial pain, 15(44%) subjects showed hyperthermia on the pain site in the thermography, 8(23.5%)exhibited hyperthermia on the site opposed to the pain site, and 11(32.4%) did not show any significant thermal change. One patient without craniofacial pain showed hyperthermia on the site opposed to the site of disc displacement without reductin. 2. Of 35 patients with craniofacial pain or disc displacement, 24(68.6%) subjects showed a significant thermal difference between symptomatic and asymptomatic sides of the face, but 11(31.4%) did not show any difference. 3. Of 17 patients with pain but with normal disc-condyle relationship, 8(47.1 subjects showed hyperthermia on the pain site, 4(23.5%) showed on the site opposed to the pain site, and 5(29.4%) did not show any significant thermal change. 4. Or 13 patients with pain and disc displacement with reduction, 6(46.2%) subjects showed hyperthermia on the pain site, 3(23.1%) showed on the site opposed to the pain site, and 4(30.8%) did not show any significant thermal change. 5. 15 healthy subjects did not show any thermal differences between the both sides of the face.

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Empirical Analysis of the Effect of EU ETS on the CO2 Emission (유럽공동체 배출권거래제 도입 효과에 대한 실증분석)

  • Kim, Hyun;Lee, Gwanghoon
    • Environmental and Resource Economics Review
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    • v.19 no.4
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    • pp.875-896
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    • 2010
  • Using the difference in differences (DID) estimation method, this paper analyzes the effect of European Union's Emission Trading Scheme (EU ETS) on the reduction of per capita $CO_2$ emission among the twenty five participating countries. For this, the panel dataset of forty two European countries for the period 1990~2007 is constructed. Special attention is paid to the bias of the standard errors in the DID estimation due to the presence of serial correlation in the error terms. The results shows quite a robust effect of EU ETS on the reduction of per capita $CO_2$ emission among the participating countries regardless of the calculation methods of standard errors. The results also shows that the increased implicit tax rate on energy has a robust effect on the reduction of per capita $CO_2$ emission. On the contrary, the estimation results regarding the effects of per capita GDP and population density on the per capita $CO_2$ emission seem inconsistent. In particular, the environmental Kuznets curve is not statistically supported with the use of robust standard errors.

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To Donate or Not: Effects of Price Difference and Reference Groups on Intention to Purchase a Donation Option (소비자는 기부를 선택할까: 가격차이, 준거집단이 기부옵션 선택에 미치는 영향력 검증)

  • Sei Jin Park;Sojin Jung
    • Fashion & Textile Research Journal
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    • v.26 no.3
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    • pp.239-250
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    • 2024
  • This study aims to investigate the factors influencing donation intention when the option to donate is presented during a purchase decision. Through an experimental design, we examined how price differences and reference group effects impact donation intention. We created stimuli with three price difference conditions (high, low, and control) and two levels of referent power (high and low), and involved 480 Korean consumer panels in the experiments. After controlling for psychological reactance levels, a two-way MANCOVA confirmed the main effects of price difference and referent power but found no interaction effect between these variables. Notably, consumers were less likely to feel guilty for not selecting the donation option when its price was slightly higher than that of the non-donation option, compared to the scenario where the prices were the same. Additionally, consumers exposed to high referent power experienced greater irritation, guilt, and shame if they did not choose the donation option compared to the low referent power group. Multiple regression results showed that guilt significantly influenced the intention to purchase a donation option, whereas irritation and shame did not. These findings suggest that understanding situational factors such as price differences and referent power can help develop effective marketing strategies and encourage voluntary participation in donations.

Meal-related time use of employees living in one-person and multi-person households: A comparison focused on gender and age differences (1인가구 근로자의 식사 관련 시간 분석: 다인가구와의 비교 및 성별·연령대별 차이를 중심으로)

  • Kim, Yoo-Kyung
    • Journal of Family Resource Management and Policy Review
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    • v.22 no.3
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    • pp.21-41
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    • 2018
  • This study determined the characteristics of meal-related time use among employees living in one-person and multi-person households by conducting a comparison focused on gender and age differences. Among the questionnaires distributed to employees during the 2014 Korean Time Use Survey, 19,692 were used for final analysis. The results were as follows: First, the one-person households had shorter meal-related time use than did the multi-person households, except for the time spent having snacks and beverages. Second, meal-related time use was generally longer in non-working days than in workdays. Third, gender differences in meal-related time use were observed, with the more significant ones being the differences in time devoted to meal preparation and dishwashing. Fourth, in both the one-person and multi-person households, women spent a longer amount of time preparing meals and washing dishes than did men, but this difference was greater in multi-person households. Fifth, old individuals spend a longer time preparing meals and washing dishes than did young individuals. Policies must be enforced to improve the quality of diets in one-person households. Such households should also be provided nutrition education to increase their awareness of the importance of healthy and regular meals. Another essential requirement of policy is the provision of gender equality education for both the one-person and multi-person households.

A COMPARISON STUDY ON DENTAL TREATMENT TIME OF PATIENTS WITH DIFFERENT TYPES OF DISABILITIES (장애유형별 치과진료시 소요시간에 관한 비교연구)

  • Lee, Wooram;Kim, Young-Jae
    • The Journal of Korea Assosiation for Disability and Oral Health
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    • v.10 no.2
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    • pp.78-83
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    • 2014
  • The objective of this study was to confirm the validity of classification of dental disability by measuring the dental treatment time required for disabled patients and identify the disability type that requires more of chair time. As a result of measuring a total of 123 patients who were admitted to the Seoul dental hospital for the disabled on Oct. 2014, I was able to make the following conclusions: 1. For dental counseling and check-up, the chair time did not show significant differences between the different types of disability. 2. For periodontal treatment, restorative treatment, root canal treatment, and surgical treatment, the difference of the chair time for dentally disabled patients was significantly longer than that of non-dentally disabled patients. 3. The difference in the total chair time for prosthetic treatment was statistically insignificant. However, each of the prosthetic treatment steps did show statistically significant differences.

Analysis of Consumer Preferences for Branded and Imported Pork (국내 브랜드 돈육과 수입산 돈육의 선호도 분석)

  • Kim, Gyewoong;Kim, Minjin;Ok, Youngsoo;Kim, Hackyoun
    • Journal of the Korean Society of Food Culture
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    • v.29 no.4
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    • pp.342-347
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    • 2014
  • This survey was conducted to investigate consumer preferences for branded and imported pork, including favorite cooking styles. Data were collected from a total of 252 consumers and analyzed. The results are summarized as follows. Consumers of branded pork showed a moderate preference "moderate" (54%). There was no significant difference in consumer preference for branded pork according to educational level or living area. However, there was a significant difference according to yearly income (p<0.05). Consumers in the high-income group preferred branded pork more than those in the low-income group. Most consumers did not like imported pork (64.6%). There was no significant difference in consumer preference for imported pork according to educational level or living area, whereas there was in the yearly income group (p<0.05). Whereas low-income consumers did not like imported pork, high-income consumers did. The royalty for purchasing of branded pork was shown "3.65" out of 5 points. Whereas there was no significant difference according to educational level, there was for living area and yearly income (p<0.05). Consumers living in large cities or having low income showed high royalty of purchase for branded pork. The royalty for purchase of imported pork was "2.08" out of 5 points. Significant differences for purchase royalty of imported pork were observed according to educational level, living area, and yearly income group (p<0.05). Consumers responded that they liked roasted pork (47.6%). Secondly, consumers liked stew (16.7%). There were no significant differences among various cooking styles in any of the groups.

Changes in the Clothing Expenditure using Difference in Difference Model: Comparison between Korean and U.S. Households (이중차이 모형을 적용한 1990년대 중반 이후 한국과 미국소비자의 피복비 지출 변화 분석 및 비교)

  • Lee, Mi-Young
    • Korean Journal of Human Ecology
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    • v.21 no.2
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    • pp.349-362
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    • 2012
  • This paper explores differences demonstrated by changes of consumers' clothing expenditure in Korea and the United States since the mid-1990s. Evidence for this study was extrapolated from annual data provided by the Household Expenditure Survey, which was carried out in Korea between 1996 and 2008, and the Consumer Expenditure Survey, which was carried out in the United States during the same time period. The results include: (1) The proportion of the clothing expenditure decreased during the subject period in both Korea and the United States; (2) The decrease in proportional clothing expenditure was greater in Korea than in the United States; (3) Although the relative prices of clothes decreased greatly during this period in both countries, it was determined that the decrease in clothing prices in the United States was greater when compared to those in Korea; and (4) By using the DID(Difference in difference) model, the author contends that a decrease in clothing purchases contributed to the decrease of prices for clothing in the United States, while in Korea, the decrease in prices for clothing was also impacted by other factors including changes in household expenditures for education and communication.

Masking Level Difference: Performance of School Children Aged 7-12 Years

  • de Carvalho, Nadia Giulian;do Amaral, Maria Isabel Ramos;de Barros, Vinicius Zuffo;dos Santos, Maria Francisca Colella
    • Journal of Audiology & Otology
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    • v.25 no.2
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    • pp.65-71
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    • 2021
  • Background and Objectives: In masking level difference (MLD), the masked detection threshold for a signal is determined as a function of the relative interaural differences between the signal and the masker. Study 1 analyzed the results of school-aged children with good school performance in the MLD test, and study 2 compared their results with those of a group of children with poor academic performance. Subjects and Methods: Study 1 was conducted with 47 school-aged children with good academic performance (GI) and study 2 was carried out with 32 school-aged children with poor academic performance (GII). The inclusion criteria adopted for both studies were hearing thresholds within normal limits in basic audiological evaluation. Study 1 also considered normal performance in the central auditory processing test battery and absence of auditory complaints and/or of attention, language or speech issues. The MLD test was administered with a pure pulsatile tone of 500 Hz, in a binaural mode and intensity of 50 dBSL, using a CD player and audiometer. Results: In study 1, no significant correlation was observed, considering the influence of the variables age and sex in relation to the results obtained in homophase (SoNo), antiphase (SπNo) and MLD threshold conditions. The final mean MLD threshold was 13.66 dB. In study 2, the variables did not influence the test performance either. There was a significant difference between test results in SπNo conditions of the two groups, while no differences were found both in SoNo conditions and the final result of MLD. Conclusions: In study 1, the cut-off criterion of school-aged children in the MLD test was 9.3 dB. The variables (sex and age) did not interfere with the MLD results. In study 2, school performance did not differ in the MLD results. GII group showed inferior results than GI group, only in SπNo condition.