• Title/Summary/Keyword: Cohort Method

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Growth of Copepod $Acartia$ $hongi$ Nauplii in Kyeonggi Bay, Korea

  • Youn, Seok-Hyun;Choi, Joong-Ki
    • Korean Journal of Environmental Biology
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    • v.29 no.4
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    • pp.379-387
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    • 2011
  • Copepod nauplii plays an important role as a linker between the microbial food web and classical food chain in marine ecosystem and is an essential food source for early stage of many larval fishes. Study on the influencing factors on the growth of copepod naupliar stages has been rarely carried out in despite of these ecological significances. Many studies have shown that food availability and temperature are major factors to influence copepod growth. However, due to the complicated environment parameters in coastal ecosystem, the relationships between growth of copepods and influencing factors are still unclear under the natural condition. Growth rates of the copepod $Acartia$ $hongi$ nauplii were measured in Kyeonggi Bay from February to December 2001. $Acartia$ $hongi$ is numerically abundant and widespread predominant species in the coastal regions of the Yellow Sea and occurs continuously throughout the year, with a maximum peak in late spring. The naupliar growth rates of $Acartia$ $hongi$ by the artificial cohort method varied from 0.03 to 0.18 $day^{-1}$, with a mean of 0.09 $day^{-1}$. The overall naupliar growth rates showed a significantly positive relationship with the variation in water temperature. However, Previous study reported that the growth rates of adult $Acartia$ $hongi$ were primarily influenced by the variation in chlorophyll-$a$. Therefore, these differences demonstrated that the influencing factors of growth did not correspond with the developmental stages. The results of this study suggest that the dissimilarity of growth between nauplius and adult female resulted from the size-dependant difference in food availability and the growth of older developmental stages containing adults are more food-dependent than juveniles.

Identifying Compound Risk Factors of Disease by Evolutionary Learning of SNP Combinatorial Features (SNP 조합 인자들의 진화적 학습 방법 기반 질병 관련 복합적 위험 요인 추출)

  • Rhee, Je-Keun;Ha, Jung-Woo;Bae, Seol-Hui;Kim, Soo-Jin;Lee, Min-Su;Park, Keun-Joon;Zhang, Byoung-Tak
    • Journal of KIISE:Computing Practices and Letters
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    • v.15 no.12
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    • pp.928-932
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    • 2009
  • Most diseases are caused by complex processes of various factors. Although previous researches have tried to identify the causes of the disease, there are still lots of limitations to clarify the complex factors. Here, we present a disease classification model based on an evolutionary learning approach of combinatorial features using the data sets from the genetics and cohort studies. We implemented a system for finding the combinatorial risk factors and visualizing the results. Our results show that the proposed method not only improves classification accuracy but also identifies biologically meaningful sets of risk factors.

Improved Survival of Cervical Cancer Patients in a Screened Population in Rural India

  • Jayant, Kasturi;Sankaranarayanan, Rengaswamy;Thorat, Ranjit V;Muwonge, Richard;Hingmire, Sanjay J;Panse, Nandkumar S;Shastri, Surendra S;Malvi, Sylla G;Nene, Bhagwan
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.11
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    • pp.4837-4844
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    • 2016
  • Objectives: To describe the survival experience of cervix cancer patients in a screened rural population in India. Methods: Included 558 cervical cancer patients diagnosed in 2000-2013 in a cohort of 100,258 women invited for screening during 2000-2003. The primary end point was death from cervical cancer. We used the Kaplan-Meier method to estimate cumulative observed survival and Cox proportional hazards regression to assess the effect of patient characteristics on survival after diagnosis. Results: Of the 558 cases included, 143 (26%) and 114 (20%) were diagnosed in stages IA and IB respectively; 252 (45.2%) were dead, and 306 (54.8%) were alive at the last follow-up. The overall 5-year observed survival was 60.5%. The 5-year survival of stage IA patients was 95.1% and 5.3% for stage IV patients. All surgically treated stage IA patients, 94.1% of stage IB patients receiving intracavitary radiotherapy, 62% of stage IIB, 49% of stage III and 25% of stage IV patients receiving radiotherapy survived for 5 years. Conclusion: Higher 5-year survival in our study than elsewhere in India is due to the high proportion of early stage cancers detected by screening combined with adequate treatment, resulting into a favourable prognosis.

Three-dimensional analysis of dental decompensation for skeletal Class III malocclusion on the basis of vertical skeletal patterns obtained using cone-beam computed tomography

  • Kim, Yong-Il;Choi, Youn-Kyung;Park, Soo-Byung;Son, Woo-Sung;Kim, Seong-Sik
    • The korean journal of orthodontics
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    • v.42 no.5
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    • pp.227-234
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    • 2012
  • Objective: To evaluate the presurgical orthodontic tooth movement of mandibular teeth after dental decompensation for skeletal Class III deformities on the basis of vertical skeletal patterns. Methods: This cohort was comprised of 62 patients who received presurgical orthodontic treatment. These patients were divided into 3 groups according to their vertical skeletal patterns. Changes in the positions of the mandibular central incisor, canine, premolar, and 1st molar after presurgical orthodontic treatment were measured using a cone-beam computed tomography (CBCT) superimposition method. Results: The incisors moved forward after dental decompensation in all 3 groups. The canines in group I and the 1st premolars in groups I and III also moved forward. The incisors and canines were extruded in groups I and II. The 1st and 2nd premolars were also extruded in all groups. Vertical changes in the 1st premolars differed significantly between the groups. We also observed lateral movement of the canines in group III and of the 1st premolar, 2nd premolar, and 1st molar in all 3 groups (p < 0.05). Conclusions: Movement of the mandibular incisors and premolars resolved the dental compensation. The skeletal facial pattern did not affect the dental decompensation, except in the case of vertical changes of the 1st premolars.

Comparison of Machine Learning Methodology in COPD Cohort Data (COPD 코호트 자료에서의 Machine Learning 방법론 비교)

  • Jeong, Hyeon-Myeong;Park, Heon-Jin;Rhee, Chin-Kook;Lee, Jong-min
    • The Journal of Bigdata
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    • v.2 no.2
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    • pp.115-128
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    • 2017
  • Recently, Machine Learning Methods are widely used with high prediction performance. But if the limit of the data is solved by the statistical technique, It can, lead to higher prediction performance than the existing one. In this study, the SMOTE method is used to solve the imbalance problem in the longitudinal and imbalanced data. As a result, It, was confirmed that the prediction performance increases. Additionally, Although, studies on COPD have been actively conducted, only studies that are related to acute exacerbation have been conducted. So there are no studies on the prediction of acute exacerbation through multiple perspectives and predictive models for various factors. In this study, We examined the factors related to acute exacerbation of COPD and constructed a personalized specific disease prediction model.

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Electromagnetic Field Exposure and Male Breast Cancer Risk: A Meta-analysis of 18 Studies

  • Sun, Jing-Wen;Li, Xiao-Rong;Gao, Hong-Yu;Yin, Jie-Yun;Qin, Qin;Nie, Shao-Fa;Wei, Sheng
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.1
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    • pp.523-528
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    • 2013
  • Background: The possibility that electromagnetic fields (EMF) exposure may increase male breast cancer risk has been discussed for a long time. However, arguments have been presented that studies limited by poor quality could have led to statistically significant results by chance or bias. Moreover, data fo the last 10 years have not been systematically summarized. Methods and Results: To confirm any possible association, a meta-analysis was performed by a systematic search strategy. Totals of 7 case-control and 11 cohort studies was identified and pooled ORs with 95% CIs were used as the principal outcome measures. Data from these studies were extracted with a standard meta-analysis procedure and grouped in relation to study design, cut-off point, exposure assessment method, adjustment and exposure model. A statistical significant increased risk of male breast cancer with EMF exposure was defined (pooled ORs = 1.32, 95% CI = 1.14-1.52, P < 0.001), and subgroup analyses also showed similar results. Conclusions: This meta-analysis suggests that EMF exposure may be associated with the increase risk of male breast cancer despite the arguments raised.

Survival Rate of Extrahepatic Cholangiocarcinoma Patients after Surgical Treatment in Thailand

  • Pattanathien, Pisit;Khuntikeo, Narong;Promthet, Supannee;Kamsa-ard, Supot
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.1
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    • pp.321-324
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    • 2013
  • Background: Intra- and extrahepatic cholangiocarcinoma (CCA) is the most common cancer in Thailand, especially in the northeast region. Most extrahepatic CCA patients consult a doctor at a late stage. Surgery is still the best treatment. Objectives: The aim of this study was to evaluate survival rates and factors affecting survival in extrahepatic CCA patients following surgery at Srinagarind Hospital, Khon Kaen University, Thailand. Materials and Methods: A retrospective cohort study was conducted with 58 patients who were diagnosed and treated by surgical resection by the same surgeon at Srinagarind Hospital between 2005 and 2009. The patients were followed up until death or the end of the study (31 December, 2011). Survival rates were calculated by the Kaplan-Meier method, and the Cox proportional hazard model was used to identify independent prognostic factors. Results: The total follow-up time was 1,215 person-months, and the mortality rate was 50 per 100 person-years. The cumulative 1-, 3-, and 5-year survival rates were 62.1%, 21.7% and 10.8%, respectively. The median survival time after resection was 15 months. After adjusting for age, gender, lymph node metastasis and histological type, resection margin remained as a statistically significant prognostic factor for survival following surgery. A positive resection margin was associated with a 2.3-fold higher mortality rate than a negative margin. Conclusions: Resection margins are important prognostic factors affecting survival of extrahepatic CCA patients after surgery. A negative resection margin can reduce the mortality rate by 56%.

A Survey of Student Perceptions, Academic Achievement, and Satisfaction of Team-based Learning in a Nursing Course (간호교육에서 팀 기반학습(Team-based Learning)의 적용에 관한 연구)

  • Roh, Young-Sook;Ryoo, Eon-Na;Choi, Dong-Won;Baek, Sun-Sook;Kim, Sang-Suk
    • The Journal of Korean Academic Society of Nursing Education
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    • v.18 no.2
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    • pp.239-247
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    • 2012
  • Purpose: This study is to assess the level of student perceptions, academic achievement, satisfaction, and their relationships in a medical-surgical nursing course using team-based learning (TBL). Method: Four-hour TBL sessions were given in a structured three-phase sequence in a cohort of 261 second year nursing students. Results: Mean perceptions of TBL was $6.64{\pm}5.11$, and $8.30{\pm}4.11$ for perceptions of teamwork. On a 7-point scale, the mean satisfaction score was $4.85{\pm}1.41$, and 64.0% of nursing students were satisfied with TBL compared to lecture. Group readiness assurance test score was significantly higher than individual readiness assurance test score (t=-16.76, p<.001). Perceptions of TBL (F=1.40, p=.245), perceptions of team work (F=1.55, p=.202) and satisfaction (F=0.81, p=.489) was not different by the level of students' academic achievement on items related TBL. Conclusion: Results indicates that TBL was an effective instructional strategy including favorable perceptions and satisfaction for nursing students. TBL could be an adjunct educational strategy for undergraduate nursing education.

Relationship between tooth loss and carotid intima-media thickness in Korean adults

  • Chin, Ui-Jung;Ji, Suk;Lee, Su-Young;Ryu, Jae-Jun;Lee, Jung-Bok;Shin, Chol;Shin, Sang-Wan
    • The Journal of Advanced Prosthodontics
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    • v.2 no.4
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    • pp.122-127
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    • 2010
  • PURPOSE. The aim of this study was to examine the relationship between tooth loss and sub-clinical atherosclerosis in Korean adults. MATERIALS AND METHODS. The subjects were part of a cohort study conducted in Ansan city by the Korea University medical school as part of the Korean Genome project. 749 subjects over than 40 years old were evaluated. After taking panoramic radiography, the amount of tooth loss was calculated. The intima-media thickness (IMT) was assessed by using ultrasonography at the common carotid artery. Traditional cardiovascular risk factors for atherosclerosis were also evaluated. The relationship between tooth loss and the IMT was evaluated using ANOVA with Scheffe's multiple comparison method in univariate analysis. Multiple regression analysis was also performed to determine the significance between the IMT and tooth loss. RESULTS. With age, tooth loss increased, but there was no significant increase in other traditional cardiovascular risk factors. Univariate analysis revealed the IMT to be positively related with the amount of tooth loss. Regression analysis of the IMT in the anterior and posterior tooth loss revealed that only the posterior tooth loss was significantly related with the IMT at all sites of the common carotid artery (right far wall, P = .015; left far wall, P = .008; right near wall, P < .001; left near wall, P = .001). CONCLUSION. This study verified the positive relationship between the increased tooth loss at the posterior area and the accumulation of atheroma in arteries.

Breast Density and Risk of Breast Cancer in Asian Women: A Meta-analysis of Observational Studies

  • Bae, Jong-Myon;Kim, Eun Hee
    • Journal of Preventive Medicine and Public Health
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    • v.49 no.6
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    • pp.367-375
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    • 2016
  • Objectives: The established theory that breast density is an independent predictor of breast cancer risk is based on studies targeting white women in the West. More Asian women than Western women have dense breasts, but the incidence of breast cancer is lower among Asian women. This meta-analysis investigated the association between breast density in mammography and breast cancer risk in Asian women. Methods: PubMed and Scopus were searched, and the final date of publication was set as December 31, 2015. The effect size in each article was calculated using the interval-collapse method. Summary effect sizes (sESs) and 95% confidence intervals (CIs) were calculated by conducting a meta-analysis applying a random effect model. To investigate the dose-response relationship, random effect dose-response meta-regression (RE-DRMR) was conducted. Results: Six analytical epidemiology studies in total were selected, including one cohort study and five case-control studies. A total of 17 datasets were constructed by type of breast density index and menopausal status. In analyzing the subgroups of premenopausal vs. postmenopausal women, the percent density (PD) index was confirmed to be associated with a significantly elevated risk for breast cancer (sES, 2.21; 95% CI, 1.52 to 3.21; $I^2=50.0%$). The RE-DRMR results showed that the risk of breast cancer increased 1.73 times for each 25% increase in PD in postmenopausal women (95% CI, 1.20 to 2.47). Conclusions: In Asian women, breast cancer risk increased with breast density measured using the PD index, regardless of menopausal status. We propose the further development of a breast cancer risk prediction model based on the application of PD in Asian women.