Objectives. This study surveyed medical students attending clerkship to assess their attitude toward and knowledge about breastfeeding, and self-confidence to manage common breastfeeding problems. Methods. A self-report questionnaire was administered to the 323 medical students at four medical colleges in Taegu in May 1997. The response rate was 92.9%, but the respondents used in the final data analysis were 245 (75.8%) due to missing variables. Results. Overall, respondents showed equivocal attitudes toward breastfeeding (mean score 2.9 on a 6-point scale). Knowledge about breastfeeding was substantially low with the median % correct 39.2%. Of nine knowledge areas, weak areas were especially 'contraindications and barriers to breastfeeding', 'use of breastfeeding aids', 'expression and storage of breast milk'. Those reported to be confident to manage common breastfeeding problems were only 25.7%. Correlations between knowledge and self-confidence were not statistically significant except in college A (r=0.35, p
We followed prospectively some hospital-delivered mothers to identify characteristics of those not initiated breast-feeding and predictors of breast-feeding discontinuation in monthly telephone interviews. Recruits were composed of 482 mothers who delivered their babies at one university hospital and one OB/GYN clinic in September to November 1991. Breast-feeding discontinuation was defined as switch to 100% formula lasting more than one week regardless of solid foods. Average age of the study subjects was 27.3 years of age(standard deviation 3.2). Multiple logistic regression analysis indicated native place, occupation, method of delivery and method of feeding considered to be better for maternal health were statistically significant(p years of education were 2.63 times (95% confidence interval, CI ) more likely to discontinue than those with less than 9 years of education and those with more than 13 years of education were 3.55 time (95% CI ). Compared with house wife, mothers with part-time jobs were 1.99 times (95% CI ) more likely to discontinue and those with employed full-time were 1.55 times (95% CI ). These results suggest that the predictors of initiation and discontinuation of breast-feeding may be different and different target populations should be selected to promote initiation and to prevent discontinuation of breast-feeding according to the period after birth.
비예혼합 화염의 안정성에 관한 종래의 연구는 연료노즐이나 퀄의 형상에 초점을 많은 맞추어 왔으나 화염안정화에 중요한 연료의 후퇴거리 및 공기노즐의 홀 형상에 대한 연구는 상대적으로 부족하여 이에 관한 연구가 절실한 실정이다. 따라서, 본 연구에서는 메탄 분류 후퇴거리 및 2 차 공기의 홀 형상에 따른 연소특성을 관찰하기 위해 동축 삼중관 형태의 버너를 설계하였다. 1 차 공기는 스월러를 통하여 분류하였고, 2 차 공기는 홀 형상 및 슬릿 형상의 각 노즐로부터 분류되었다. 본 연구에 사용된 실험실 스케일 버너로부터 2 차 공기의 유속은 화염의 형태에 영향을 끼치는 것을 알 수 있었다. 후퇴거리의 경우 공급관외경의 절반에 해당하는 거리로 설정했을 때 화염이 안정적으로 존재하고, 휘도는 더욱 높아짐을 알 수 있었다.
The purpose of this study was to evaluate results of cervix cytology screening in the community and to determine the risk factors of cervical abnormality. Branch of Daejeon city and Chungnam Province, The Planed Parenthood Federation of Korea had conducted cervical cancer screening of 146,848 married women in Chungnam province from 1995 to 1999. Cervical cancer screening was Pap smear using cytolgic brush swab by trained nurse. Women who had abnormal finding of 1st Pap smear screening were followed re- examination and 2nd close examination. Crude prevalence rate of cytologic abnormalities for 1st screening results was 0.63% in 1995- 1999(1995 0.68%, 1996 0.59%, 1997 0.70%, 1998 0.56%, 1999 0.62%). Crude prevalence rate of above class III for 1st screening results was 0.61%, but crude prevalence rate of above class III for the results of re- examination and 2nd close examination was 2.2/ 1000. The false-positive rate of class III, IV and V for positive findings were defined above class II(cervicitis) results were 52.6%, 26.9% and 19.0%, respectively. And the false- positive rate of class III, IV and V for positive findings were defined above class III(dysplasia) results were 75.3%, 46.2% and 47.6%, respectively. Major predictors of risk factors for abnormal results of cervix screening on the multiple logistic regression were age, educational attainment and living area. The false-positive rate of cervix cytology screening in the community were highest result so cervix cytology screening should be improve for better diagnostic power. And the finding of logistic regression would be understand within the limit of experimental trials on the relationship between cervical disease and risk factors.
Atomization is affected by the internal flow of liquid in the nozzle as well as the interaction between liquid and the surrounding air at the spray downstream. Cavitation which is generated in the nozzle is known for having a strong influence on atomization. Recent research shows that cavitation in the circular nozzle had a cylindrical shape that is symmetrical to the nozzle axial However the cavitation shape of elliptical nozzles looked like a horseshoe in that the cavitation length for the major axis plane is longer than that of the minor axis plane. The purpose of this study is to numerically investigate the internal nozzle flow and cavitation characteristics in a circular nozzle and an elliptical nozzle. The computational fluid dynamics (CFD) code FLUENT 6.2 was used to perform the numerical simulation of the cavitating flow in the nozzles. A comparison between the cavitation shape of the numerical results and those of the experimental results was made to validate a numerical solution. As a consequence of this study, in the case of the elliptical nozzle, the static pressure of the working fluid at the major axis plane was decreased near the vapor pressure along the orifice wall at a longer distance when compared with the minor axis plane. Also, the radial velocity distribution was different between the major axis plane and the minor axis plane when the working fluid was flowing into the orifice inlet.
연소실 내의 주류 공기유동에 미치는 영향을 최소화하면서 미립화 및 혼합특성을 향상시키기 위한 방법으로 주류공기 유동에 대해 수직방향의 연료분사 방식이 실용 엔진에서 많이 사용되고 있고, 관련 연구도 활발히 보고되고 있다. 본 연구는 가스터빈이나 램젯 엔진에서 사용되고 있는 수직분사의 분무특성은 실험적으로 조사하고, 단일 및 이중 수직분사에 따른 침투길이를 측정함으로써 선행연구에 의해 보고된 결과와 비교하였다. 또한 압력과 모멘텀 플럭스비 변화에 따른 침투길이, 분무입경 등의 분무 특성을 연구하였다. 특히, 이중 수직분사의 침투길이는 단일 수직분사의 침투길이에 비해 전단의 수직분사의 영향으로 후단의 수직분사 길이가 약 20% (Lh=4mm) 증가함을 확인할 수 있었다.
Objectives : Face-to-face interviews were conducted to investigate the relationship between blood pressure and the impairment of cognitive function in rural elderly (N=932) aged 60-64 in Dalsung County, April to September in 1996 Methods : Impairment of cognitive function was defined as a score of less than 23 by the Korean version of the Mini-Mental State Examination (MMSEK). Blood pressure was measured once in each subject using a portable automatic sphygmomanometer. Results : By univariate logistic regression on males, no category of systolic blood pressure bore statistical significance. Groups with diastolic blood pressures of, less than 80 mmHg, 90-94 mmHg, and more than 95mmHg had odds ratios of more than one compared with the reference group (80-89 mmHg). This was most significant in the group with blood pressures lower than 80 mmHg, which had a statistically significant odds ratio of 1.68 (95% confidence interval CI; 1.02-2.75). No category of blood pressure was statistically significant in females. Multivariate logistic regression for males, with adjustment for age, educational attainment, smoking, alcoholic drinking, body mass index, atherosclerotic disease, and antihypertensive medication use, did not alter the odds ratios significantly in terms of systolic blood pressure. However, the group with diastolic blood pressure of less than 80 mmHg had an increased odds ratio of 2.01 (95% CI; 1.15-3.52) compared with the reference group. In females, systolic blood pressure did not alter the odds ratio, but the group with a diastolic blood pressure of less than 80 mmHg had a statistically significant odds ratio of 0.57 (95% CI; 0.37-0.89). Conclusions : These results suggest that the relationship between blood pressure and cognitive function status is stronger diastolic than systolic blood pressure and that there is a complex relationship between blood pressure and cognitive function by sex.
본 연구는 타원형 노즐과 원형 노즐 내부에서 발생되는 cavitation의 발생 및 성장을 실험적으로 관찰하였다. 원형 노즐과 타원형 노즐의 cavitation 특성을 가시화 하기위해 투명한 아크릴로 노즐을 제작하였다. 실험에 사용된 노즐들은 같은 단면적으로 제작되었으며, 타원형 노즐의 경우 형상비(a/b)를 다르게 하였다. 분사압력의 증가에 따라 노즐내부 유동은 no cavitation, cavitation, hydraulic flip 영역으로 나뉘어졌다. 노즐의 형상에 상관없이 no cavitation과 cavitation 영역에서는 분사압력의 증가에 따라 유량은 증가하며, 유출계수는 감소하는 경향을 나타냈다. 그러나 hydraulic flip 영역에서의 유량계수는 일정한 값을 나타냈다. 타원형 노즐은 원형 노즐에 비해 높은 cavitation number에서 cavitation이 성장, 발달하였다. 특히 타원형 노즐에서는 장축의 cavitation length가 단축보다 길게 나타났다.
'%3e%3cg id='b'%3e%3cpath id='a' stroke='%23000' stroke-width='2' d='M-6-25H6m-12 3H6m-12 3H6'/%3e%3cuse xlink:href='%23a' y='44'/%3e%3c/g%3e%3cpath stroke='%23fff' d='M0 17v10'/%3e%3ccircle r='12' fill='%23cd2e3a'/%3e%3cpath fill='%230047a0' d='M0-12A6 6 0 0 0 0 0a6 6 0 0 1 0 12 12 12 0 0 1 0-24z'/%3e%3c/g%3e%3cg transform='rotate(-123.69)'%3e%3cuse xlink:href='%23b'/%3e%3cpath stroke='%23fff' d='M0-23.5v3M0 17v3.5m0 3v3'/%3e%3c/g%3e%3c/svg%3e)