• Environmental and Resource Economics Review
• /
• v.25 no.2
• /
• pp.199-228
• /
• 2016

This study investigates the effects of economic factors and forest environments on rural residential area development in seven north central states of the U.S. by focusing on the relative importance of not only economic factors but also forest environments by forest type as core drivers of residential development. An empirical model of locations and magnitudes of population changes since 1950 in the north central region is first constructed, and then a panel model with fixed effects for counties is used to explain population growth by age group over time at the county level. Then a set of three equations is estimated for three major age groups, and a cross-sectional model is estimated for the last time period that regresses county-level environmental amenity variables on fixed effects coefficients for counties. Finally, an equation explaining changes in rural housing density is estimated. The results imply that immigrant age is a key factor influencing the choice of the place of residence and that the effects of environmental amenity factors on population growth and subsequent housing development in a county vary according to the age group.

• The Journal of the Korea Contents Association
• /
• v.11 no.5
• /
• pp.308-316
• /
• 2011

Familial concordance of vascular risk factors is well understood and there are many studies about inter-spouse concordance of the risk factors for coronary heart disease. However, there are no studies for inter-spousal relation of the risk factors in cerebrovascular disease patients. We analysed inter-spouse correlation of cerebrovascular risk factors in patients admitted our hospital due to stroke and their spouses. There was statistically significant inter-spouse concordance in the presence of hypertension(p=0.025) and carotid IMT(r=0.479, p=0.001). However, the further age-adjusted analysis revealed no significant result. Differently from the results of previous studie,, the present study shows no significant spousal concordance. Althought there are tendencies of spousal concordance in some risk factors, the age is major determinant.

• Proceedings of the KSCN Conference
• /
• 2004.05a
• /
• pp.416.2-417
• /
• 2004

심혈관계 질환(CVD, Cardiovascular disease, CHD, Coronary heart disease)은 심장의 관상동맥에 염증반응과 혈전으로 인해 죽상경화중이 생겨 관상동맥이 좁아지거나 막히는 결과를 초래하는 질환으로 관상동맥질환, 고혈압, 말초혈관질환, 협심증, 심근경색증, 중풍 등이 포함된다. 심혈관계 질환의 위험인자들에는 서구화된 식생활, 유전, 나이, 성, 고혈압, 당뇨, 고지혈증, 비만, 운동부족, 스트레스, 흡연, 가족력 등이 있다. 그러나 식생활의 변화로 인한 심혈관계 질환과 생화학적 지표의 변화 및 관련 기전에 대한 연구는 거의 없었다.(중략)

• Tuberculosis and Respiratory Diseases
• /
• v.49 no.4
• /
• pp.474-485
• /
• 2000

Background : Current studies on multimodal strategy for N2 non-small cell lung cancer are being high interest, have drawn much attention. N2 lung cancer, however, is composed of is divided into several sub groups with that have different prognoses. The prognostic factors still remain controversial. Methods : Between January 1990 and June 1999, 180 patients with N2 lung cancer who underwent surgical resection were investigated, excluding 10 of these for surgical mortality. All patients underwent mediastinal lymph node dissection. 20 clinicopathologic factors were investigated by univariable and multivariable analyses to identify significant prognostic factors among resected N2 disease. Results : The overall 5-year survival rate was 20.6%. Multivariable analyses among overall patients revealed 3 significant prognostic factors : Age, Histologic type, Vascular invasion. Based on the result, 49 patients with both age more than 60 and pathologic Non-squamous cell showed a 5-year survival of 5.0%, whereas 37 patients with neither of the factors showed a 5-year survival of 56.6%(p<0.001). And 12 patients with both vascular invasion and pathologic Non-squamous cell showed a 5-year survival of 11.9%, whereas 67 patients with neither of the factors showed a 5-year survival of 33.6%(p=0.01). Conclusion : The prognosis of surgically resected N2 disease varies according to the 3 significant prognosis factors. Tumor size may be an additional influencing factor in the prognosis of N2 disease.

• Childhood Kidney Diseases
• /
• v.13 no.1
• /
• pp.21-25
• /
• 2009

Last year, an epidemic of infantile urinary stone disease developed in China. Investigation revealed that melamine-tainted diary product caused urinary stone in these infants. Young infants were susceptible to the melamine toxicity and dehydration or other stone-prone factors aggravated the toxicity. Melamine-related urinary stones were small, multiple, and mainly composed of uric acid, thus conservative treatment of hydration and urine alkalinization worked well in majority of the patients.

• Bulletin of the Korean Space Science Society
• /
• 2003.10a
• /
• pp.23-23
• /
• 2003

천체의 거리는 다양한안 방법을 사용하여 직접 혹 간접적으로 측정되어왔다. 특히 우주배경복사를 측정하는 인공위성 관측의 정밀도가 혁명적으로 향상됨에 따라 우주의 나이는 수 % 이내의 정밀도로 결정할 수 있는 수준으로 발전하였다. 우주의 규모가 구체적으로 정의되는 가운데 우주의 절대적인 크기를 제시하기 위하여 천체의 거리를 측정하는데 사용되는 표준등불로 세페이드 변광성 이외에 식쌍성이 새롭게 대두되었다. 이 논문에서는 식쌍성이 거리척도의 표준등불이 될 수 잇는지 검증하기 위하여 광도곡선과 시선속도곡선이 잘 알려진 알골형 쌍성 식쌍성 RY Aqr, RX Gem, RS Vul을 선정하여 거리를 산출하였다. 별을 선정한 기준은 2색 이상의 광도곡선이 발표되고, 이중 분광쌍성으로 시선속도곡선이 각 성분별로 잘 관측되어 발표되고, IUE 관측 자료가 있는 알골형 쌍성이다. 거리 산출과정에서 간접적으로 유추하여 얻는 인자를 줄이기 위하여, 광도곡선으로부터 별의 상대적인 크기를 구하고, 시선속도곡선으로부터 공전궤도의 장반경을 구하고, 별의 에너지 분포 곡선으로부터 별의 온도를 측정하였다. 위 3종류의 관측 결과를 종합하여 식쌍성의 물리적 인자와 거리를 구하였다. 이와 같은 방법으로 구한 거리는 히파크러스를 이용하여 관측한 시차와 비교하였다.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2011.04a
• /
• pp.112-115
• /
• 2011

본 연구는 분자동역학 전산모사를 통하여 나일론 6 고분자재료 및 나이론 6 고분자재료를 기지재료로 사용하는 나노복합재에 대하여 인장하중을 부여하고, 인장에 의하여 발생하는 구조적 변화 및 물질의 구조적 특성과 열전도 특성 사이의 상관관계를 규명하였다. 나노복합재의 열전도특성을 변화시키는 주요 인자로는 나노입자, 인장에 의한 고분자 사슬의 배열 변화, 자유부피(free volume)의 변화이다. 고분자 사슬이 열전달 방향으로 배열될 경우 음양자(phonon)의 흐름을 가속화하여 열전도특성이 증가하며, 반면 자유부피의 증가는 음양자의 산란을 증가시켜 열전도특성이 저하된다. 따라서 서로 상반작용을 하는 두 인자가 복합적으로 작용하여 열전도 특성을 결정한다. 인장 하중이 부여됨에 따라 시스템의 열전도특성이 증가하며, 각 시스템의 증가 정도는 시스템의 구조적 특성에 따라 서로 다르다.

• Journal of Korea Society of Industrial Information Systems
• /
• v.13 no.2
• /
• pp.1-7
• /
• 2008

This paper presents a method to design a repetitive controller that is robust to variations in the system parameters. The uncertain parameters are specified probabilistically by their probability distribution functions. Instead of working with the distribution functions directly, the repetitive controller is designed from a set of models that are generated from the specified probability functions. With this multiple-model design approach, any number of uncertain parameters that follow any type of distribution functions can be treated. furthermore, the controller is derived by minimizing a frequency-domain based cost function that produces monotonic convergence of the tracking error as a function of repetition number. Numerical illustrations show how the proposed multiple-model design method produces a repetitive controller that is significantly more robust than an optimal repetitive controller designed from a single nominal model of the system.

• Journal of Nutrition and Health
• /
• v.44 no.1
• /
• pp.29-40
• /
• 2011

The purpose of this study was to examine the association among bone mineral density (BMD), biochemical bone markers, nutrients, and salt intake in premenopausal and postmenopausal women. We evaluated 431 subjects who visited a health promotion center of a university hospital between January 2008 and July 2009. We excluded those who were taking medications or who had an endocrine disorder affecting osteoporosis. The subjects were divided into premenopausal (n = 283) and postmenopausal (n = 143) women. We evaluated the correlation among BMD of the lumbar spine, femoral neck, and total femoral, as well as biochemical bone markers, hormone, serum profiles, general characteristics, nutrient intakes, and food intake frequencies. From a stepwise multiple regression analysis, lumbar spine BMD was positively correlated with weight (p < 0.001) and negatively correlated with osteocalcin (OC)(p < 0.001), Femoral neck BMD was positively correlated with weight (p < 0.001) and negatively correlated with C-telopeptide (CTx) and alkaline phosphatase (ALP)(p < 0.001, p < 0.05). In premenopausal women, femoral total BMD was positively correlated with BMI (p < 0.001) and negatively correlated with CTx (p < 0.001). In postmenopausal women, lumbar spine BMD was positively correlated with calcium intake (p < 0.01) and negatively correlated with sodium intake (p < 0.01). Femoral neck and femoral total BMD were both positively correlated with weight (p < 0.001), and femoral neck BMD was negatively correlated with age and ALP (p < 0.001, p < 0.05). Femoral total BMD was negatively correlated with age and OC (p < 0.001, p < 0.01). These results suggest that reducing sodium intake may play an important role delaying bone resorption and preventing a decrease in BMD.

• Journal of Yeungnam Medical Science
• /
• v.17 no.1
• /
• pp.75-81
• /
• 2000

Background: Systemic embolism, especially, cerebral infarction is one of the most important complications in patients with mitral stenosis. The authors analyzed the some factors that could predict the development of cerebral infarction in cases of mitral stenosis and propose preventive therapeutic measures. Methods: Retrospective study of 127 patients with rheumatic mitral stenosis was performed by analyzing their medical records for transthoracic(TTE) or transesophageal echocardiography(TEE) over a 12 months period. The patients were divided into two groups according to the presence (Group I: n=26, age: $55.0{\pm}13$ years) or absence (Group II: n=101, age: $48.5{\pm}13$ years) of cerebral infarction. No significant difference was observed between the two groups with respect to sex and functional class. Results: Patients in group I were older ($55.0{\pm}13$ vs $48.5{\pm}13$;p<0.05). had more dilated left atrial size($5.10{\pm}0.48$ vs $4.81{\pm}0.70$;p<0.05) and smaller mitral surface area($1.01{\pm}0.39$ vs $1.21{\pm}0.45$;p<0.05). In Group 1. the incidence of atrial fibrillation(22 out of 26 vs 57 out of 101;p<0.05) and spontaneous left intra-atrial contrast phenomenon(22 out of 26 vs 44 out of 101;p<0.05) was more frequently observed. On multivariate analysis. atrial fibrillation and anticoagulant therapy were the independent predictive factors. Conclusion: Age, left atrial dilatation, the severity of mitral stenosis, the presence of spontaneous contrast, and especially the presence of atrial fibrillation are the main predictive factors of the development of cerebral infarction in mitral stenosis. Patients presenting one or several of these factors may benefit from prophylactic anticoagulant treatment.