• 제목/요약/키워드: Differences-in-Differences (DiD)

검색결과 20건 처리시간 0.02초

수산부문 기술혁신이 OECD 회원국의 성장률에 미친 효과 (Effects of Fisheries Technological Innovation on Growth per Capita across OECD Countries)

  • 이윤숙;장재봉
    • 한국산학기술학회논문지
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    • 제18권4호
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    • pp.349-357
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    • 2017
  • 최근 해양자원에 대한 환경적 제약에 대한 관심 증대와 다른 산업에 비해 상대적으로 뒤쳐진 수산부문의 성장으로 인해 많은 국가들은 수산부문의 다양한 성장 방안을 고려하고 추진하고 있다. 본 연구는 경제협력개발기구(OECD) 회원국들의 패널자료를 이용하여 수산부문의 기술혁신이 회원국 국민 1인당 국내총생산(GDP)에 미치는 영향을 분석하였다. 이를 위해 이중차분모형(DiD)과 Granger 인과성 검증방법을 이용하여 수산부문 연구개발(R&D) 지출, 특허, 고용 등의 수산부문 기술혁신과 경제 성장간의 상호 연관성과 파급효과를 분석하였다. 패널모형 분석에서는 24개 OECD 회원국들 가운데 수산부문의 기술개발 분야의 선도국가들인 노르웨이, 독일, 덴마크, 미국, 캐나다, 한국을 대상으로, 인과성 검증은 자료의 제약으로 OECD 회원국들 중에서 노르웨이, 미국, 캐나다, 한국만을 대상으로 국한하였다. 분석 결과, 수산부문에 대한 정부의 R&D 지출, 기술개발, 고용이 확대될수록 OECD 회원국들의 1인당 GDP는 증가하는 것으로 나타났다. 그러나, 이들 변수들 간의 상호연관성은 존재하지 않는 것으로 나타났다. 인과성 검증 결과, GDP와 수산부문 기술발전 사이의 인과성은 국가마다 상당한 차이를 보이는 것으로 나타났다.

Comparison of different impression techniques for edentulous jaws using three-dimensional analysis

  • Jung, Sua;Park, Chan;Yang, Hong-So;Lim, Hyun-Pil;Yun, Kwi-Dug;Ying, Zhai;Park, Sang-Won
    • The Journal of Advanced Prosthodontics
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    • 제11권3호
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    • pp.179-186
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    • 2019
  • PURPOSE. The purpose of this study was to compare two novel impression methods and a conventional impression method for edentulous jaws using 3-dimensional (3D) analysis software. MATERIALS AND METHODS. Five edentulous patients (four men and one woman; mean age: 62.7 years) were included. Three impression techniques were used: conventional impression method (CI; control), simple modified closed-mouth impression method with a novel tray (SI), and digital impression method using an intraoral scanner (DI). Subsequently, a gypsum model was made, scanned, and superimposed using 3D analysis software. Mean area displacement was measured using CI method to evaluate differences in the impression surfaces as compared to those values obtained using SI and DI methods. The values were confirmed at two to five areas to determine the differences. CI and SI were compared at all areas, while CI and DI were compared at the supporting areas. Kruskal-Wallis test was performed for all data. Statistical significance was considered at P value <.05. RESULTS. In the comparison of the CI and SI methods, the greatest difference was observed in the mandibular vestibule without statistical significance (P>.05); the difference was < 0.14 mm in the maxilla. The difference in the edentulous supporting areas between the CI and DI methods was not significant (P>.05). CONCLUSION. The CI, SI, and DI methods were effective in making impressions of the supporting areas in edentulous patients. The SI method showed clinically applicability.

진단분류에 따른 측두하악장애 환자의 임상적 및 심리적 특징 (The Clinical and Psychological Characteristics of the Patients with Temporomandibular Disorders according to Its Diagnostic Subgroups)

  • 김정호;기우천;최재갑
    • Journal of Oral Medicine and Pain
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    • 제22권1호
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    • pp.45-63
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    • 1997
  • A Study was conducted to examine the nature and extent of psychological differences among diagnostic subgroups of temporomandibular disorders(TMD) patients and to whether psychological distress acts as a precipitator for TMD or is only an incidental consequence of the discomfort and frustrations presented by the disorder. Ninty six TMD patients and ninty seven non-TMD dental patients were included for the study as an experimental group and control group. TMD patients were classified into subgroups according to their primary pain sites and labeled as: 1) Myogenous TMD group; 2) Arthrogenous TMD group; 3) Mixed TMD group. After Hilkimo indices were rated from patient history and clinical examination, levels of psychological distress were measured using SRRS (Social Readjustment Rating Scale) and MMPI (Minnesota Multiphasic Personality Inventory). Outcomes from Helkimo indices, SRRS, and MMPI were assessed in terms of diagnostic subgroups and pain chronicity. The relationship between SRRS and MMPI scores were also assessed. The results were as follows : 1. The TMD patients showed higher frequencies of AiII, DiII, and DiIII of Helkimo indices than those in the control subjects. 2. The chronic TMD patients showed lower frequencies of DiII and DiIII of Helkimo indices than those in the acute group. 3. The arthrogenous TMD group showed higher frequencies of DiII and DiIII of Helkimo indices than those in the myogenous TMD group. 4. The TMD patients showed higher SRRS mean score than that in the non-TMD patients. 5. The SRRS mean score was highest in the myogenous TMD group and lowest in the arthrogenous TMD group. 6. The chronic TMD patients showed higher SRRS mean score than the acute TMD group. 7. The TMD patients showed higher MMPI mean scores on the Hs, D, Hy, and Pt scales than those in the non-TMD patients. 8. The MMPI mean scores on th Hs, D, and Hy scales were higher than of other MMPI scales in the TMD patients as well as in the myogenous and the mixed TMD group and they showed 1-3-2(Hs, -Hy, -D.) profile pattern, conversion "V". 9. The MMPI mean scores on the Hs and Hy scales were higher in all subgroups of TMD patients than non-TMD patients. 10. Although there were no significant differences in the MMPI mean scores on all the scales between the acute and the chronic groups of all TMD patients, the chronic myogenous TMD group showed higher MMPI mean scores on the Hs, Hy, Pa, and Pt scales than the acute myogenous TMD group. 11. There were positive correlationships between SRRS score and each MMPI scores on the Hs and Hy scales.Hy scales.

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mPW1PW91 Conformational Study of Di-t-butyl-dinitro-tetramethoxysulfonylcalix[4]arene

  • Choe, Jong-In
    • Bulletin of the Korean Chemical Society
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    • 제32권1호
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    • pp.100-104
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    • 2011
  • The structures of the conformers for 1,3-di-t-butyl-2,4-dinitro-tetramethoxysulfonylcalix[4]arene (1) and 1,2-di-t-butyl-3,4-dinitro-tetramethoxysulfonylcalix[4]arene (2) were optimized using DFT BLYP and mPW1PW91/6-31G(d,p) (hybrid HF-DF) calculation methods. We have analyzed the total electronic and Gibbs free energies and the differences between the various conformations (cone, partial-cone (PC), 1,2-alternate, and 1,3-alternate) of 1 and 2. For both compounds, the 1,3-alternate (1,3-A) conformers were calculated to be the most stable, which correlate very well with the experimental results. The orderings of the relative stability of 1 and 2 that resulted from the mPW1PW91/6-31G(d,p) calculations are the following: 1: 1,3-A (syn) > PC (syn) > PC (anti) > 1,2-A (anti) > CONE (syn); 2: 1,3-A (anti) > PC (anti) > PC (syn) > 1,2-A (anti) > 1,2-A (syn) > CONE (syn). The BLYP/6-31G(d) calculated IR spectra of the most stable 1,3-A conformers of 1 and 2 are compared.

스테레오 카메라를 이용한 안면부 측정의 재현성과 정확도에 대한 마네킨을 이용한 연구: 직접 인체계측, Digitizer, Stereophotogrammetry의 비교 연구 (Manikin Model Study on Reproducibility and Accuracy of Maxillofacial Measurements Determined by Stereocamera: Comparative Study of Direct Anthropometry, Digitizer and Stereophotogrammetery)

  • 정연욱;양지웅;정광;국민석;오희균
    • Maxillofacial Plastic and Reconstructive Surgery
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    • 제34권1호
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    • pp.17-25
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    • 2012
  • Purpose: Recently, a three dimensional approach to hard and soft tissues of the maxillofacial area has been widely used. This study was to evaluate the reproducibility and accuracy of a stereocamera compared to actual measurement methods using a digital caliper and digitizer. Methods: The stereoscopies of 7 head dummies with different sizes and shapes were obtained using a Di3D system (Dimensional Imaging, Glasgow, UK) after marking reference points on facial areas. From the obtained stereoscopy, 10 measurements representing the width, height and depth of each of the facial sections of the dummy were measured twice using a three dimensional reverse engineering software program (RapidForm$^{TM}$ 2006, Inus, Seoul, Korea). The x, y, and z coordinates of each of the three dimensional measurements were obtained and distances between two points were calculated. All procedures were repeated twice. The actual measurement method was performed twice, directly on dummies, using a digital caliper and values were compared with the previously determined values. Results: The results were as follows. In the ANOVA analysis, there were no significant statistical differences among the three measurement methods. In the Bonferroni analysis, with adjustments applied for multiple comparisons, there was no difference between actual measurement methods using a digitizer and a digital caliper. However, there was some difference between using a stereocamera and actual measurement methods using a digitizer and a digital caliper in values of $Ex_{Rt}-Ex_{Lt}$, $En_{Rt}-En_{Lt}$, $Ala_{Rt}-Ala_{Lt}$, $Ch_{Rt}-Ch_{Lt}$, G-Pg', $Ala_{Rt}$-Prn, $Ala_{Rt}$-Prn. The mean value for technical error in measurement (TEM) in Di3D (0.98 mm) was slightly higher than for a digital caliper (0.17 mm) and a digitizer (0.30 mm). In an intraclass correlation coefficient (ICC) there were no significant differences among the three measurement methods, but the Di3D system with the stereocamera showed relatively lower reproducibility compared to actual measurement methods using a digitizer and a digital caliper. Conclusion: These results indicate that some complementary measures may be needed to improve accuracy and reproducibility in the Di3D system with stereocamera.

농업용 직접분사식 디젤기관에서 함산소연료 적용시 배기배출물 특성 연구 (A Study on Characteristics for Exhaust Emission with Oxygenated Fuel in an Agricultural DI Diesel Engine)

  • 최승훈;오영택;서정덕
    • Journal of Biosystems Engineering
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    • 제32권5호
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    • pp.279-283
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    • 2007
  • In this study, the potential possibility of oxygenates on di-ether group (DBE, dibutyl ether) was investigated as an additives for an agricultural direct injection diesel engine. It tested to estimate change of engine performance and exhaust emission characteristics for the commercial diesel fuel and oxygenates additives blending fuel which has four kinds of mixed ratio. The smoke emission of blending fuel (diesel fuel 80 vol-% + DBE 20 vol-%) was reduced in comparison with diesel fuel, that is, it was reduced approximately 26% at 2500 rpm, full load. And, power, torque and brake specific energy consumption didn't have large differences. But, NOx emission of blended fuel was increased compared with commercial diesel fuel.

Effect on quanti-quality milk and mozzarella cheese characteristics with further increasing the level of dried stoned olive pomace in diet for lactating buffalo

  • Taticchi, A.;Bartocci, S.;Servili, M.;Di Giovanni, S.;Pauselli, M.;Mourvaki, E.;Zilio, D. Meo;Terramoccia, S.
    • Asian-Australasian Journal of Animal Sciences
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    • 제30권11호
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    • pp.1605-1611
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    • 2017
  • Objective: Following a previous report, an experiment was conducted to determine the effect of increasing level of dried stoned olives pomaces (DSOP) in the diet of lactating buffaloes on milk and mozzarella cheese yield and characteristics. Methods: Sixteen pluriparous buffaloes distributed into two groups were fed an isoenergetic (0.9 milk forage unit/kg) and isoprotein (149 g/kg dry matter [DM] of crude protein) diet, with or without DSOP. Each animal received 17 kg DM/d. Samples of forages and concentrates were weekly collected and used for duplicate chemical analyses. Individual milk samples from each control were analyzed for chemical and coagulating parameters and daily production of mozzarella cheese was estimated. At the end of the trial, bulk milk of each group was processed to produce mozzarella cheese and chemical (fat, protein, ash, pH) composition, fatty acids composition, carotenoids and tocopherols content were determined. A sensory test was also performed. The oxidative stability was measured on mozzarella cheese and on governing liquid. Results: No significant differences were observed, neither for milk yield and body condition score, nor for milk characteristics. The fat was higher (p<0.05) in mozzarella of DSOP fed group but, saturated fatty acids were lower and unsaturated higher (p<0.01). Furthermore, lower atherogenic (p<0.01), and thrombogenic (p<0.05) indices were found in mozzarella cheese of DSOP fed group. In addition, the administration of DSOP did not affect the mozzarella cheese oxidative stability and no negative effect was found in the sensory properties. Conclusion: No contraindications appeared for the inclusion of DSOP in the diet of lactating buffaloes. Besides, important effects on mozzarella cheese quality were obtained, such as a modification of fat content and attributes with an increment in the mono-unsaturated. Additionally, a lower saturated/unsaturated ratio and atherogenic and thrombogenic indices suggest an improvement of dietetic and nutritional characteristics of mozzarella cheese.

Assessment of three European fuel performance codes against the SUPERFACT-1 fast reactor irradiation experiment

  • Luzzi, L.;Barani, T.;Boer, B.;Cognini, L.;Nevo, A. Del;Lainet, M.;Lemehov, S.;Magni, A.;Marelle, V.;Michel, B.;Pizzocri, D.;Schubert, A.;Uffelen, P. Van;Bertolus, M.
    • Nuclear Engineering and Technology
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    • 제53권10호
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    • pp.3367-3378
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    • 2021
  • The design phase and safety assessment of Generation IV liquid metal-cooled fast reactors calls for the improvement of fuel pin performance codes, in particular the enhancement of their predictive capabilities towards uranium-plutonium mixed oxide fuels and stainless-steel cladding under irradiation in fast reactor environments. To this end, the current capabilities of fuel performance codes must be critically assessed against experimental data from available irradiation experiments. This work is devoted to the assessment of three European fuel performance codes, namely GERMINAL, MACROS and TRANSURANUS, against the irradiation of two fuel pins selected from the SUPERFACT-1 experimental campaign. The pins are characterized by a low enrichment (~ 2 wt.%) of minor actinides (neptunium and americium) in the fuel, and by plutonium content and cladding material in line with design choices envisaged for liquid metal-cooled Generation IV reactor fuels. The predictions of the codes are compared to several experimental measurements, allowing the identification of the current code capabilities in predicting fuel restructuring, cladding deformation, redistribution of actinides and volatile fission products. The integral assessment against experimental data is complemented by a code-to-code benchmark focused on the evolution of quantities of engineering interest over time. The benchmark analysis points out the differences in the code predictions of fuel central temperature, fuel-cladding gap width, cladding outer radius, pin internal pressure and fission gas release and suggests potential modelling development paths towards an improved description of the fuel pin behaviour in fast reactor irradiation conditions.

Impact of Caspase-8 (CASP8) -652 6N Del and D302H Polymorphisms on Prostate Cancer in Different Ethnic Groups

  • Zhang, Cheng-Dong;Li, Hong-Tao;Liu, Kun;Lin, Zhi-Di;Peng, Qi-Liu;Qin, Xue;He, Min;Wu, Hua;Mo, Zeng-Nan;Yang, Xiao-Li
    • Asian Pacific Journal of Cancer Prevention
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    • 제15권18호
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    • pp.7713-7718
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    • 2014
  • Background: Despite evidence suggesting roles for caspase-8 (CASP8) -652 6N del and D302H polymorphisms in prostate cancer (PCa), the association of these polymorphisms with PCa risk remains inconclusive. Therefore, a meta-analysis was performed to more precisely estimate the association of CASP8 -652 6N del and D302H polymorphisms with PCa susceptibility. Materials and Methods: A comprehensive literature search was conducted to identify all case-control studies of CASP8 D302H and -652 6N del polymorphisms and PCa risk. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of the association and the precision of the estimate, respectively. Results: Nine -625 6N del studies and 4 D302H studies were included. CASP8 -652 6N del and D302H polymorphisms were not significantly associated with PCa risk in the overall analyses. However, in the subgroup analysis stratified by ethnicity, -625 6N del was significantly associated with PCa risk in the East Asian and Indian populations under the recessive model. Furthermore, the subgroup analysis strongly suggested that D302H was associated with lower PCa risk in the Non-Indian population under the dominant model. Conclusions: In our meta-analysis, ethnic-specific differences were evident in the association of CASP8-625 6N del and D302H polymorphisms with PCa risk.

ACE 삽입 및 결손 유전자 다형성과 HDL 콜레스테롤과의 관련성 (The Relationship between ACE I/D Polymorphism and HDL Cholesterol)

  • 유창훈;곽종영;김나영;노미숙;정갑열;이용환;김정만;김준연;홍영습
    • Journal of Preventive Medicine and Public Health
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    • 제39권6호
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    • pp.505-510
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    • 2006
  • Objectives : The purpose of this study is to evaluate the association of the angiotensin converting enzyme (ACE) insertion/deletion (I/D) polymorphism with cardiovascular disease risk factors. Methods : Out of a total of 608 middle-aged adults who visited local health centers, 424 subjects (104 male, 320 female) who had not been diagnosed with hypertension, diabetes mellitus, or hyperlipidemia were included in this study. ACE genotypes were determined in all subjects by polymerase chain reaction methods. Results : Statistical differences in high-density lipoprotein (HDL) cholesterol levels according to ACE genotype were observed using ANOVA (p<0.05), but no differences were found in other cardiovascular risk factors. Specifically, men with the DD and DI genotypes had significantly lower HDL cholesterol levels than those with the 11 genotype based on the LSD multi-comparison test (p<0.05). Conclusions : In men, the D-allele of the ACE I/D polymorphism was significantly associated with reduced HDL cholesterol levels. In the future, larger studies are needed to confirm this relationship between ACE I/D polymorphism and HDL cholesterol.