• Title/Summary/Keyword: Wilcoxon Rank Sum Test

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Mass Interception Fractions and Weathering Half-lives of Iodine-131 and Radiocesium in Leafy Vegetables Observed after the Fukushima Daiichi Nuclear Power Plant Accident

  • Tagami, Keiko;Uchida, Shigeo
    • Journal of Radiation Protection and Research
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    • v.46 no.4
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    • pp.178-183
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    • 2021
  • Background: This study was carried out to provide environmental transfer parameter values to estimate activity concentrations of these radionuclides in agricultural crops when direct contamination occurred. Materials and Methods: Mass interception fractions (FBs) and weathering half-lives (Tws) of 131I and radiocesium were calculated using openly available monitoring data obtained after the Fukushima Daiichi Nuclear Power Plant accident. FB is the ratio between the initial radioactivity concentration of a radionuclide retained by the edible part of the plant (Bq·kg-1 fresh weight [FW]) and the amount of deposited radionuclide in that area (Bq·m-2). Tw values can be calculated using activity concentrations of crops decreased with time after the initial contamination. Results and Discussion: Calculated FB and Tw values for 131I and radiocesium were mostly obtained for leafy vegetables. The analytical results showed that there was no difference of FBs between 131I and radiocesium by t-test; geometric mean values for leafy vegetables cultivated under outdoor conditions were 0.058 and 0.12 m2·kg-1 FW, respectively. Geometric mean Tw value of 131I in leafy vegetables grown under outdoor conditions was 8.6 days, and that of radiocesium was 6.6 days; there was no significant difference between Tw values of these radionuclides by Wilcoxon rank sum test. Conclusion: There was no difference between 131I and radiocesium for FBs and Tws. By using these factors, we would be able to carry out a rough estimation of the activity concentrations of 131I and radiocesium in the edible part of leafy crops when a nuclear accident occurred.

Comparison of longitudinal treatment effects with facemask and chincup therapy followed by fixed orthodontic treatment on Class III malocclusion (상악전방견인장치와 이모장치 및 고정식 교정장치 치료를 받은 III급 부정교합 환자의 치료효과에 대한 종단적 비교)

  • Lee, Nam-Ki;Baek, Seung-Hak
    • The korean journal of orthodontics
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    • v.39 no.6
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    • pp.362-371
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    • 2009
  • Objective: The purpose of this study was to compare the longitudinal treatment effects of facemask with rapid maxillary expansion (FM/RME) and chincup (CC) therapy followed by fixed orthodontic treatment (FOT) in Class III malocclusion (CIII) patients. Methods: The samples consisted of twenty-one CIII patients who had similar skeletal and dental characteristics before FM/RME or CC therapy and good retention results (Class I molar/canine relationship and positive overbite/overjet) after FOT (Group 1, FM/RME, n = 11; Group 2, CC, n = 10). Lateral cephalograms were taken before (T0) and after FM/RME or CC therapy (T1), and after FOT and retention (T2). Skeletal and dental variables were measured. Mann-Whitney U-test and Wilcoxon signed-rank test were used for statistical analysis. Results: During T0-T1, FM/RME therapy induced forward movement of point A, and labioversion of the upper incisors. Both groups showed posterior repositioning of the mandible. FM/RME resulted in increase of the vertical dimension; however, CC caused an increase in articular angle and decrease in gonial angle. During T1-T2, both groups exhibited forward growth of point A. Group 1 showed forward growth and counterclockwise rotation of the mandible and increase of IMPA; however, Group 2, showed increase of ANS-Me/N-Me and decrease of overbite. Conclusions: The key factor for successful FM/RME and CC therapy and good retention results might be a harmonized forward growth of the maxilla that could keep pace with the growth and rotation of the mandible.

Analysis of Use of Government Support for Palliative Care Units in Korea (말기암환자 완화의료 전문기관 운영 지원비 사용 평가)

  • Kim, Hyo-Young;Yoo, Eun-Sil;Kim, Yeol;Kong, Kyoung-Ae;Song, Hye-Young;Choi, Jin-Young
    • Journal of Hospice and Palliative Care
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    • v.14 no.4
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    • pp.212-217
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    • 2011
  • Purpose: Since 2005, the Ministry of Health & Welfare has provided financial support to promote palliative care for terminal cancer patients. We analyzed how palliative care facilities used the funding between 2006 and 2010. Methods: Frequency analysis was conducted by the item of expenditure based on fiscal reports of the palliative care facilities. Linear regression analysis was performed to examine a trend over time. Kruskal-Wallis test and Wilcoxon rank-sum test were used to compare expenditure items, the number of provision of financial support and type of palliative care units. Results: About a half of the fund was spent to pay care givers salary, improve facilities and purchase equipment regardless of the year, the number of financial support provided or facility type. By year, the operation cost for palliative care program and the education cost for health care workers have significantly increased in linear regression analysis (P<0.01). However, the amount of financial support for the low income group has decreased over years (P=0.024). This trend was affected by evaluation criteria and weight. Conclusion: The government aid for palliative care units has been used to improve facilities and equipment. Moreover, desirable changes were noted such as a higher portion of expenses for program operation and care giver training to enhance the quality of care. However, the evaluation criteria need to be adjusted to prevent any further decrease in the support provided to the low income group.

Effect of Breast-feeding Education and Follow-up care on the Breast-feeding Rate and the Breast-feeding Method - Focused on Home Visit and Phone Counselling - (모유수유교육과 추후간호방법이 산모의 모유수유실천율과 모유수유방법에 미치는 효과 - 가정방문과 전화상담을 중심으로 -)

  • Park, Sook-Hee;Koh, Hyo-Jung
    • Women's Health Nursing
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    • v.7 no.1
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    • pp.30-43
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    • 2001
  • This was a pre-experimental study to confirm the breast-feeding ability and effect of follow up care on the breast-feeding rate and the breast-feeding method by the mother-infant breast-feeding assessment tool for the mothers who got the breast-feeding education. The subjects were 46 mothers who experienced normal delivery of infants at a college hospital in K-city, Kyungsangbuk-do, from July 1 to October 21, 2000. The instrument for data obtainment were The Mother-Infant Breast-Feeding Assessment Tool of Johnson et al. (1999), and The Breast- Feeding Method Measurement Tool of Jeong, Geum-hee(1997). This instrument was reliable, showing Cronbach $\alpha$.751. This study classified them into 3 groups: at high risk for breast-feeding failure, at risk for breast-feeding problems, and at low risk for breast-feeding failure by the mother-infant breast-feeding assessment tool on the day of discharge from the hospital after delivering individual breast-feeding education to the subjects. This study investigated the breast-feeding rate and the breast-feeding method through mail questionnaire at the four week after childbirth, and through the phone counselling and the home visit for follow up care at the first week and the second week after childbirth. The sixth week after childbirth, this study investigated the breast-feeding rate by phone. The data analyzed the hypothesizes by $x^2$-test, paired t-test, ANOVA, Wilcoxon signed rank test, Wilcoxon rank sum test and trend analysis using SPSS/PC+ WIN 10.0 program. The results were as follows : 1) Hypothesis 1-1, "there won't be any difference the breast-feeding rate of a group at risk for breast-feeding failure by the time elapsed" was supported through constant the breast-feeding rate, because changes in the breast-feeding rate by the time elapsed after childbirth wasn't statistically significant(t= -1.501, p=.270). Hypothesis 1-2, "there won't be any difference the breast-feeding rate of group at low risk for breast-feeding failure by the time elapsed" was supported through constant the breast-feeding rate, because changes in the breast-feeding rate by the time elapsed after childbirth wasn't statistically significant(t=-1.732, p=.225). 2) Hypothesis 2-1, "there won't be any difference between the breast-feeding method of group at risk for breast-feeding failure for four weeks after childbirth and just after childbirth” was rejected, because the mean point of post test appeared to be higher than that of pre test(t=-7.267, p=.000). Hypothesis 2-2, "there won't be any difference between the breast-feeding method of the group at low risk for breast-feeding failure for four weeks after childbirth and just after childbirth" was rejected, because the mean point of post test appeared to be higher than that of pre test(t=-2.501, p=.012). 3)The 3rd hypothesis, "there won't be any difference between breast-feeding method of groups at risk for breast-feeding problems and at low risk for breast-feeding failure at the 4th week after childbirth and just after childbirth" didn't show any difference between the breast-feeding method of groups at risk for breast-feeding problems and at low risk for breast-feeding failure in the advance test(t=-1.521, p=.130) but there was difference between them in post test (t=-2.012, p=.044). As a result, the 3rd hypothesis was supported by pre test, but it was rejected by post test. In conclusion, this study confirmed breast- feeding education and follow up care just after childbirth were effective for the breast-feeding rate and method. Accordingly, it is proposed that successful nursing intervention of breast-feeding to be necessary by continuously providing follow up care through the mother-infant breast-feeding assessment tool as well as to execute individual breast-feeding education to mothers just after childbirth.

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A Study of Improvement for the Prediction of Groundwater Pollution in Rural Area: Application in Keumsan, Korea (농촌지역 지하수의 오염 예측 방법 개선방안 연구: 충남 금산 지역에의 적용)

  • Cheong, Beom-Keun;Chae, Gi-Tak;Koh, Dong-Chan;Ko, Kyung-Seok;Koo, Min-Ho
    • Journal of Soil and Groundwater Environment
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    • v.13 no.4
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    • pp.40-53
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    • 2008
  • Groundwater pollution prediction methods have been developed to plan the sustainable groundwater usage and protection from potential pollution in many countries. DRASTIC established by US EPA is the most widely used groundwater vulnerability mapping method. However, the DRASTIC showed limitation in predicting the groundwater contamination because the DRASTIC method is designed to embrace only hydrogeologic factors. Therefore, in this study, three different methods were applied to improve a groundwater pollution prediction method: US EPA DRASTIC, Modified-DRASTIC suggested by Panagopoulos et al. (2006), and LSDG (Land use, Soil drainage, Depth to water, Geology) proposed by Rupert (1999). The Modified-DRASTIC is the modified version of the DRASTIC in terms of the rating scales and the weighting coefficients. The rating scales of each factor were calculated by the statistical comparison of nitrate concentrations in each class using the Wilcoxon rank-sum test; while the weighting coefficients were modified by the statistical correlation of each parameter to nitrate concentrations using the Spearman's rho test. The LSDG is a simple rating method using four factors such as Land use, Soil drainage, Depth to water, and Geology. Classes in each factor are compared by the Wilcoxon rank-sum test which gives a different rating to each class if the nitrate concentration in the class is significantly different. A database of nitrate concentrations in groundwaters from 149 wells was built in Keumsan area. Application of three different methods for assessing the groundwater pollution potential resulted that the prediction which was represented by a correlation (r) between each index and nitrate was improved from the EPA DRASTIC (r = 0.058) to the modified rating (r = 0.245), to the modified rating and weights (r = 0.400), and to the LSDG (r = 0.415), respectively. The LSDG seemed appropriate to predict the groundwater pollution in that it contained land use as a factor of the groundwater pollution sources and the rating of each class was defined by a real pollution nitrate concentration.

Bone Mineral Density Measurement of Rats Using Dual-energy X-ray Absorptiometry: Precision of In Vivo Measurements for Various Skeletal Sites with or without Repositioning (쥐에서 이중에너지 방사선 흡수법을 이용한 골밀도의 측정: 다양한 골부위에서 재위치 여부에 따른 생체내 측정의 정밀도)

  • Oh, Dong-Hyun;Jung, Jae-Ho;Woo, Sang-Keun;Cheon, Gi-Jeong;Kim, Byung-Il;Choi, Chang-Woon;Lim, Sang-Moo
    • Nuclear Medicine and Molecular Imaging
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    • v.43 no.1
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    • pp.72-78
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    • 2009
  • Purpose: Bone mineral density (BMD) measurements need to be precise enough to be capable of detecting small changes in bone mass of rats. Using a regular dual-energy X-ray absorptiometry (DXA), we measured many BMD of various skeletal sites in rats to examine precision of DXA in relation to the repositioning on the bones of rats. Materials and Methods: Using DXA and small animal software, scans were performed 4 times in all 12 male rats without repositioning (Group 1a). Another four scans for 6 of 12 rats were done with repositioning between scans (Group 2). Customized regions of interest (ROIs), encapsulate the right hind limb, L1-4, skull and pelvic bones were drawn at each measurement. The precision of the measurements was evaluated by measuring the coefficient of variation (CV) of four measurements of BMD at each skeletal site of all rats with or without repositioning. Significance of differences between group 1b (six rats out of group 1a, which were come under group 2) and group2 were evaluated with Wilcoxon Signed Rank Sum Test. Results: CVs obtained at different skeletal sites of all measurements in Group 1b and 2. It was $3.51{\pm}1.20$, $ 2.62{\pm}1.20$ for the hindlimb (p=0.173), $3.83{\pm}2.02$, $4.59{\pm}2.02$ for L1-4 (p=0.600), $3.73{\pm}1.87$, $1.53{\pm}0.89$ for skull (p=0.046), and $2.92{\pm}0.60$, $1.45{\pm}0.60$ for pelvic bones (p=0.075). Conclusion: Our study demonstrates that the DXA technique has the precision necessary when used to assess BMD for various skeletal sites in rats regardless of repositioning.

Optimal design of a nonparametric Shewhart-Lepage control chart (비모수적 Shewhart-Lepage 관리도의 최적 설계)

  • Lee, Sungmin;Lee, Jaeheon
    • Journal of the Korean Data and Information Science Society
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    • v.28 no.2
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    • pp.339-348
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    • 2017
  • One of the major issues of statistical process control for variables data is monitoring both the mean and the standard deviation. The traditional approach to monitor these parameters is to simultaneously use two seperate control charts. However there have been some works on developing a single chart using a single plotting statistic for joint monitoring, and it is claimed that they are simpler and may be more appealing than the traditonal one from a practical point of view. When using these control charts for variables data, estimating in-control parameters and checking the normality assumption are the very important step. Nonparametric Shewhart-Lepage chart, proposed by Mukherjee and Chakraborti (2012), is an attractive option, because this chart uses only a single control statistic, and does not require the in-control parameters and the underlying continuous distribution. In this paper, we introduce the Shewhart-Lepage chart, and propose the design procedure to find the optimal diagnosis limits when the location and the scale parameters change simultaneously. We also compare the efficiency of the proposed method with that of Mukherjee and Chakraborti (2012).

Patient Severity Classification in a Medical ICU using APACHE Ⅲ and Patient Severity Classification Tool (APACHE Ⅲ를 이용한 중환자 분류도구의 타당도 검증)

  • Lee, Gyeong-Ok;Sin, Hyeon-Ju;Park, Hyeon-Ae;Jeong, Hyeon-Myeong;Lee, Mi-Hye;Choe, Eun-Ha;Lee, Jeong-Mi;Kim, Yu-Ja;Sim, Yun-Gyeong;Park, Gwi-Ju
    • Journal of Korean Academy of Nursing
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    • v.30 no.5
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    • pp.1243-1253
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    • 2000
  • The purpose of this study was to verify the validity of the Patient Severity Classification Tool by examining the correlations between the APACHE Ⅲ and the Patient Severity Classification Tool and to propose admission criteria to the ICU. The instruments used for this study were the APACHE Ⅲ developed by Knaus and the Patient Severity Classification Tool developed by Korean Clinical Nurses Association. Data was collected from the 156 Medical ICU patients during their first 24 hours of admission at the Seoul National University Hospital by three trained Medical ICU nurses from April 20 to August 31 1999. Data were analyzed using the frequency, $x^2$, Wilcoxon rank sum test, and Spearman rho. There was statistically significant correlations between the scores of the APACHE III and the Patient Severity Classification Tool. Mortality rate was increased as patients classification of severity in both the APACHE III and the Patient Severity Classification Tool scored higher. The Patient Severity Classification Tool was proved to be a valid and reliable tool, and a useful tool as one of the severity predicting factors, ICU admission criteria, information sharing between ICUs, quality evaluations of ICUs, and ICU nurse staffing.

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Surface changes of metal alloys and high-strength ceramics after ultrasonic scaling and intraoral polishing

  • Yoon, Hyung-In;Noh, Hyo-Mi;Park, Eun-Jin
    • The Journal of Advanced Prosthodontics
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    • v.9 no.3
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    • pp.188-194
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    • 2017
  • PURPOSE. This study was to evaluate the effect of repeated ultrasonic scaling and surface polishing with intraoral polishing kits on the surface roughness of three different restorative materials. MATERIALS AND METHODS. A total of 15 identical discs were fabricated with three different materials. The ultrasonic scaling was conducted for 20 seconds on the test surfaces. Subsequently, a multi-step polishing with recommended intraoral polishing kit was performed for 30 seconds. The 3D profiler and scanning electron microscopy were used to investigate surface integrity before scaling (pristine), after scaling, and after surface polishing for each material. Non-parametric Friedman and Wilcoxon signed rank sum tests were employed to statistically evaluate surface roughness changes of the pristine, scaled, and polished specimens. The level of significance was set at 0.05. RESULTS. Surface roughness values before scaling (pristine), after scaling, and polishing of the metal alloys were $3.02{\pm}0.34{\mu}m$, $2.44{\pm}0.72{\mu}m$, and $3.49{\pm}0.72{\mu}m$, respectively. Surface roughness of lithium disilicate increased from $2.35{\pm}1.05{\mu}m$ (pristine) to $28.54{\pm}9.64{\mu}m$ (scaling), and further increased after polishing ($56.66{\pm}9.12{\mu}m$, P<.05). The zirconia showed the most increase in roughness after scaling (from $1.65{\pm}0.42{\mu}m$ to $101.37{\pm}18.75{\mu}m$), while its surface roughness decreased after polishing ($29.57{\pm}18.86{\mu}m$, P<.05). CONCLUSION. Ultrasonic scaling significantly changed the surface integrities of lithium disilicate and zirconia. Surface polishing with multi-step intraoral kit after repeated scaling was only effective for the zirconia, while it was not for lithium disilicate.

Proposition of polytomous discrimination index and test statistics (다항판별지수와 검정통계량 제안)

  • Choi, Jin Soo;Hong, Chong Sun
    • Journal of the Korean Data and Information Science Society
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    • v.27 no.2
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    • pp.337-351
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    • 2016
  • There exist many real situations that statistical decision problems are classified into more than two categories. In these cases, the concordance statistics by the pair approach are mostly used. However, the expression of the classification of categories are ambiguous. Recently, the standardized evaluation data and re-expressed concordance statistics are defined and could be explained their meanings. They have still some non-specific problems for standard criteria of the statistics. Since these can be considered between result and truth categories additionally, two alternative concordance statistics might be proposed in this paper. Some advantages are founded that the proposed statistics could be discriminated all possible cases for two randomly selected categories. Moreover since the proposed statistics are represented with indicator functions, these could be transformed non-parametrically, so that these concordances are used for hypothesis testing.