• Title/Summary/Keyword: multiple measurements

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Mapping Precise Two-dimensional Surface Deformation on Kilauea Volcano, Hawaii using ALOS2 PALSAR2 Spotlight SAR Interferometry (ALOS-2 PALSAR-2 Spotlight 영상의 위성레이더 간섭기법을 활용한 킬라우에아 화산의 정밀 2차원 지표변위 매핑)

  • Hong, Seong-Jae;Baek, Won-Kyung;Jung, Hyung-Sup
    • Korean Journal of Remote Sensing
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    • v.35 no.6_3
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    • pp.1235-1249
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    • 2019
  • Kilauea Volcano is one of the most active volcano in the world. In this study, we used the ALOS-2 PALSAR-2 satellite imagery to measure the surface deformation occurring near the summit of the Kilauea volcano from 2015 to 2017. In order to measure two-dimensional surface deformation, interferometric synthetic aperture radar (InSAR) and multiple aperture SAR interferometry (MAI) methods were performed using two interferometric pairs. To improve the precision of 2D measurement, we compared root-mean-squared deviation (RMSD) of the difference of measurement value as we change the effective antenna length and normalized squint value, which are factors that can affect the measurement performance of the MAI method. Through the compare, the values of the factors, which can measure deformation most precisely, were selected. After select optimal values of the factors, the RMSD values of the difference of the MAI measurement were decreased from 4.07 cm to 2.05 cm. In each interferograms, the maximum deformation in line-of-sight direction is -28.6 cm and -27.3 cm, respectively, and the maximum deformation in the along-track direction is 20.2 cm and 20.8 cm, in the opposite direction is -24.9 cm and -24.3 cm, respectively. After stacking the two interferograms, two-dimensional surface deformation mapping was performed, and a maximum surface deformation of approximately 30.4 cm was measured in the northwest direction. In addition, large deformation of more than 20 cm were measured in all directions. The measurement results show that the risk of eruption activity is increasing in Kilauea Volcano. The measurements of the surface deformation of Kilauea volcano from 2015 to 2017 are expected to be helpful for the study of the eruption activity of Kilauea volcano in the future.

Cephalometric differences in obstructive sleep apnea between obese and non-obese Korean male patients (한국인 성인 남성 폐쇄성수면무호흡 환자의 측모 두부 방사선계측학적 비교)

  • Hwang, Sang-Hee;Park, In-Suk;Nam, Ki-Young;Kim, Jong-Bae;Cho, Yong-Won;Suh, Young-Sung;Ahn, Byung-Hoon;Park, Shin-Goo;Park, Hyo-Sang
    • The korean journal of orthodontics
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    • v.38 no.3
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    • pp.202-213
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    • 2008
  • Objective: The purpose of this study was to compare the cephalometric measurements of obese and non-obese Korean male patients with obstructive sleep apnea syndrome (OSA). Methods: Eighty-seven adults who had visited the Sleep Disorder Clinic Center in Keimyung University, Daegu, Korea were examined and evaluated with polysomnography (PSG) and lateral cephalogram. They were divided into 4 groups (non-obese simple snorers, obese simple snorers, non-obese OSA patients, obese OSA patients) according to AHI (Apnea-Hypopnea Index) and BMI (Body Mass Index). Results: The obese OSA group had the highest AHI among the 4 groups. The non-obese OSA group had a significantly steeper mandibular angle and shorter tongue length than the obese OSA group. The hyoid bone of the obese OSA group was positioned anterior and inferior as compared with the non-obese OSA group. Multiple regression analysis showed that tongue length in the obese OSA group and retroposition of hyoid bone in the non-obese OSA group were significant determinants for the severity of AHI. Conclusions: From a cephalometric point of view, the obese and non-obese pateints with OSA may be characterized by different pathogeneses. Therefore, they have to be managed by individualized treatment. For the obese OSA patients, weight control must be advised as a first choice and for the non-obese OSA patients, oral appliance, nasal CPAP, UPPP and others could be chosen according to the obstructive sites.

Prevalence of Hypertension and Related Risk Factors of the Older Residents in Andong Rural Area (안동 농촌지역 중년 및 노인 주민의 고혈압 유병율과 위험요인 분석)

  • Lee, Hye-Sang;Kwun, In-Sook;Kwon, Chong-Suk
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.38 no.7
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    • pp.852-861
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    • 2009
  • This study was performed to assess the risk factors associated with hypertension from Jan/2003 to Feb/2003. The subjects were 1,296 people (496 males, 800 females) aged 40 years and over living in Andong rural area. The hypertensive group was composed of 602 people (272 males, 330 females), who were diagnosed as hypertension ($SBP{\geq}140\;mmHg$ or $DBP{\geq}90\;mmHg$) for the first time at this health examination. The mean anthropometric values of body weight, body fat (%), body mass index (BMI) and waist circumference were significantly higher in hypertensive group than those in normal group. However, the biochemical measurements such as total-cholesterol (TC), triglyceride (TG), HDL-C, LDL-C and fasting blood glucose (FBG) levels did not show any difference between two groups except TG in female. The risk factors of interest in the development of hypertension were analyzed using the multiple logistic regression and expressed as odds ratio (OR) and 95% confidential interval (CI). The results showed that age, sex, obesity, waist circumference, alcohol drinking and meat intakes were risk factors for hypertension. In contrast, cigarette smoking, exercise and the increased fish, fruit and vegetable (except Kimchi) consumption, blood lipid levels and FBG were not linked with the development of hypertension. Nutrient intakes were not associated with hypertension, either. In conclusion, we cannot assert that this study established the existence of the cause-and-effect relationship between nutrient intakes and risk of hypertension in the subjects, but it does suggest that this is a question worth investigating further using a larger scale of case-control study to determine how the past exposure to some nutrient or dietary component relates to the development of the disease.

The Variations of Stratospheric Ozone over the Korean Peninsula 1985~2009 (한반도 상공의 오존층 변화 1985~2009)

  • Park, Sang Seo;Kim, Jhoon;Cho, Nayeong;Lee, Yun Gon;Cho, Hi Ku
    • Atmosphere
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    • v.21 no.4
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    • pp.349-359
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    • 2011
  • The climatology in stratospheric ozone over the Korean Peninsula, presented in previous studies (e.g., Cho et al., 2003; Kim et al., 2005), is updated by using daily and monthly data from satellite and ground-based data through December 2009. In addition, long-term satellite data [Total Ozone Mapping Spectrometer (TOMS), Ozone Monitoring Instrument (OMI), 1979~2009] have been also analyzed in order to deduce the spatial distributions and temporal variations of the global total ozone. The global average of total ozone (1979~2009) is 298 DU which shows a minimum of about 244 DU in equatorial latitudes and increases poleward in both hemispheres to a maximum of about 391 DU in Okhotsk region. The recent period, from 2006 to 2009, shows reduction in total ozone by 6% relative to the values for the pre-1980s (1979~1982). The long-term trends were estimated by using a multiple linear regression model (e.g., WMO, 1999; Cho et al., 2003) including explanatory variables for the seasonal variation, Quasi-Biennial Oscillation (QBO) and solar cycle over three different time intervals: a whole interval from 1979 to 2009, the former interval from 1979 to 1992, and the later interval from 1993 to 2009 with a turnaround point of deep minimum in 1993 is related to the effect of Mt. Pinatubo eruption. The global trend shows -0.93% $decade^{-1}$ for the whole interval, whereas the former and the later interval trends amount to -2.59% $decade^{-1}$ and +0.95% $decade^{-1}$, respectively. Therefore, the long-term total ozone variations indicate that there are positive trends showing a recovery sign of the ozone layer in both North/South hemispheres since around 1993. Annual mean total ozone (1985~2009) is distributed from 298 DU for Jeju ($33.52^{\circ}N$) to 352 DU for Unggi ($42.32^{\circ}N$) in almost zonally symmetric pattern over the Korean Peninsula, with the latitudinal gradient of 6 DU $degree^{-1}$. It is apparent that seasonal variability of total ozone increases from Jeju toward Unggi. The annual mean total ozone for Seoul shows 323 DU, with the maximum of 359 DU in March and the minimum of 291 DU in October. It is found that the day to day variability in total ozone exhibits annual mean of 5.7% in increase and -5.2% in decrease. The variability as large as 38.4% in increase and 30.3% in decrease has been observed, respectively. The long-term trend analysis (e.g., WMO, 1999) of monthly total ozone data (1985~2009) merged by satellite and ground-based measurements over the Korean Peninsula shows increase of 1.27% $decade^{-1}$ to 0.80% $decade^{-1}$ from Jeju to Unggi, respectively, showing systematic decrease of the trend magnitude with latitude. This study also presents a new analysis of ozone density and trends in the vertical distribution of ozone for Seoul with data up to the end of 2009. The mean vertical distributions of ozone show that the maximum value of the ozone density is 16.5 DU $km^{-1}$ in the middle stratospheric layer between 24 km and 28 km. About 90.0% and 71.5% of total ozone are found in the troposphere and in the stratosphere between 15 and 33 km, respectively. The trend analysis reconfirms the previous results of significant positive ozone trend, of up to 5% $decade^{-1}$, in the troposphere and the lower stratosphere (0~24 km), with negative trend, of up to -5% $decade^{-1}$, in the stratosphere (24~38 km). In addition, the Umkehr data show a positive trend of about 3% $decade^{-1}$ in the upper stratosphere (38~48 km).

Indoor Exposure and Health Risk of Polycyclic Aromatic Hydrocarbons (PAHs) via Public Facilities PM2.5, Korea (II)

  • Kim, Ho-Hyun;Lee, Geon-Woo;Yang, Ji-Yeon;Jeon, Jun-Min;Lee, Woo-Seok;Lim, Jung-Yun;Lee, Han-Seul;Gwak, Yoon-Kyung;Shin, Dong-Chun;Lim, Young-Wook
    • Asian Journal of Atmospheric Environment
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    • v.8 no.1
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    • pp.35-47
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    • 2014
  • The purpose of the study is to evaluate the pollution level (gaseous and particle phase) in the public facilities for the PAHs, non-regulated materials, forecast the risk level by the health risk assessment (HRA) and propose the guideline level. PAH assessments through sampling of particulate matter of diameter < 2.5 ${\mu}m$ ($PM_{2.5}$). The user and worker exposure scenario for the PAHs consists of 24-hour exposure scenario (WIES) assuming the worst case and the normal exposure scenario (MIES) based on the survey. This study investigated 20 PAH substances selected out of 32 substances known to be carcinogenic or potentially carcinogenic. The risk assessment applies major toxic equivalency factor (TEF) proposed from existing studies and estaimates individual Excess Cancer Risk (ECR). The study assesses the fine dusts ($PM_{2.5}$) and the exposure levels of the gaseous and particle PAH materials for 6 spots in each 8 facility, e.g. underground subway stations, child-care facilities, elderly care facilities, super market, indoor parking lot, terminal waiting room, internet caf$\acute{e}$ (PC-rooms), movie theater. For internet caf$\acute{e}$ (PC-rooms) in particular, that marks the highest $PM_{2.5}$ concentration and the average concentration of 10 spots (2 spots for each cafe) is 73.3 ${\mu}g/m^3$ (range: 6.8-185.2 ${\mu}g/m^3$). The high level of $PM_{2.5}$ seen in internet cafes was likely due to indoor smoking in most cases. For the gaseous PAHs, the detection frequency for 4-5 rings shows high and the elements with 6 rings shows low frequency. For the particle PAHs, the detection frequency for 2-3 rings shows low and the elements with 6 rings show high frequency. As a result, it is investigated that the most important PAHs are the naphthalene, acenaphthene and phenanthrene from the study of Kim et al. (2013) and this annual study. The health risk assessment demonstrates that each facility shows the level of $10^{-6}-10^{-4}$. Considering standards and local source of pollution levels, it is judged that the management standard of the benzo (a)pyrene, one of the PAHs, shall be managed with the range of 0.5-1.2 $ng/m^3$. Smoking and ventilation were considered as the most important PAHs exposure associated with public facility $PM_{2.5}$. This study only estimated for inhalation health risk of PAHs and focused on the associated cancer risk, while multiple measurements would be necessary for public health and policy.

Quality Assurance of Volumetric Modulated Arc Therapy for Elekta Synergy (Elekta Synergy 선형가속기를 이용한 입체적세기조절회전방사선치료(VMAT) 정도관리)

  • Shim, Su-Jung;Shim, Jang-Bo;Lee, Sang-Hoon;Min, Chul-Kee;Cho, Kwang-Hwan;Shin, Dong-Oh;Choi, Jin-Ho;Park, Sung-Ill;Cho, Sam-Ju
    • Progress in Medical Physics
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    • v.23 no.1
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    • pp.33-41
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    • 2012
  • For applying the quality assurance (QA) of volumetric modulated arc therapy (VMAT) introduced in Eulji Hospital, we classify it into three different QA steps, treatment planning QA, pretreatment delivering QA, and treatment verifying QA. These steps are based on the existing intensity modulated radiation therapy (IMRT) QA that is currently used in our hospital. In each QA step, the evaluated items that are from QA program are configured and documented. In this study, QA program is not only applied to actual patient treatment, but also evaluated to establish a reference of clinical acceptance in pretreatment delivering QA. As a result, the confidence limits (CLs) in the measurements for the high-dose and low-dose regions are similar to the conventional IMRT level, and the clinical acceptance references in our hospital are determined to be 3 to 5% for the high-dose and the low-dose regions, respectively. Due to the characteristics of VMAT, evaluation of the intensity map was carried out using an ArcCheck device that was able to measure the intensity map in all directions, $360^{\circ}$. With a couple of dosimetric devices, the gamma index was evaluated and analyzed. The results were similar to the result of individual intensity maps in IMRT. Mapcheck, which is a 2-dimensional (2D) array device, was used to display the isodose distributions and gave very excellent local CL results. Thus, in our hospital, the acceptance references used in practical clinical application for the intensity maps of $360^{\circ}$ directions and the coronal isodose distributions were determined to be 93% and 95%, respectively. To reduce arbitrary uncertainties and system errors, we had to evaluate the local CLs by using a phantom and to cooperate with multiple organizations to participate in this evaluation. In addition, we had to evaluate the local CLs by dividing them into different sections about the patient treatment points in practical clinics.

Prevalence of Metabolic Syndrome and Related Risk Factors of Elderly Residents in Andong Rural Area 1. Based on the Anthropometric Measurements and Health Behaviors (안동 농촌지역 중년 및 노인 주민의 대사증후군 유병율과 관련 위험요인 분석 1. 신체계측결과와 건강습관을 중심으로)

  • Lee, Hye-Sang;Kwon, Chong-Suk
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.39 no.4
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    • pp.511-517
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    • 2010
  • This study was performed to estimate the prevalence and the risk factors of metabolic syndrome in Andong rural area. A total of 1,431 people (533 males, 898 females) aged over 45 years participated in this study in 2003. The prevalence of metabolic syndrome was 38.2% (male 23.5%, female 46.9%, p<0.001). As age increased, the prevalence of the metabolic syndrome increased in female, but not in male. The major underlying components of metabolic syndrome were high blood pressure (67.1%), low HDL-cholesterol (60.6%), and abdominal obesity (39.9%). The distinctive component for male was high blood pressure (70.1%), and for female, low HDL-cholesterol (73.6%), high blood pressure (65.3%), and abdominal obesity (54.5%). Subjects having more than one component were 94.7%. The risk factors for metabolic syndrome were analyzed using the multiple logistic regression method according to gender and expressed as age-adjusted odds ratio (OR). The results of comparing female to male (OR=2.953), and of comparing obese by % body fat (M: OR=5.786, F: OR=13.498) or BMI (M: OR=3.782, F: OR=13.301) to normal body weight showed significantly higher risk for metabolic syndrome (p<0.001). Health related habits, such as smoking, alcohol drinking, and exercise, didn't show any effect on metabolic syndrome. This study revealed that the prevalence of metabolic syndrome was significantly higher in female subjects compared to both male and female, and high blood pressure was the main cause of metabolic syndrome. We suggest that the strategy for prevention or reducing the prevalence of metabolic syndrome in this area should be concentrated on reducing high blood pressure through lowering obesity and abdominal obesity.

Facial soft tissue measuring analysis of normal occlusion using three-dimensional CT imaging (3차원 CT 영상을 이용한 정상교합자의 안면 연조직 계측 분석)

  • Han, Soo-Yeon;Baik, Hyoung-Seon;Kim, Kee-Deog;Yu, Hyung-Seog
    • The korean journal of orthodontics
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    • v.35 no.6 s.113
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    • pp.409-419
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    • 2005
  • Studies for diagnostic analysis using three-dimensional (3D) CT images are recently in progress and needs for 3D craniofacial analysis are increasing in the fields of orthodontics. It is especially essential to analyze the facial soft tissue after orthodontic treatment and orthognathic surgery. In this study 3D CT images of adults with normal occlusion were taken to analyze the facial soft tissue. Norms were obtained from CT images of adults with normal occlusion (12 males, 11 females) using a computer program named V works 4.0 program. 3D coordinate planes were established using soft tissue Nasion as the reference point and a total of 20 reproducible landmarks of facial soft tissue were obtained using the multiple reconstructive sectional images (axial, sagittal and coronal images) of the V works 4.0 program: soft tissue Nasion, Pronasale, Subnasale, Upper lip center, Lower lip center, soft tissue B, soft tissue Pogonion, soft tissue Menton, Endocanthion (Rt/Lt), Alare lateralis (Rt/Lt), Cheilion (Rt/Lt), soft tissue Gonion (Rt/Lt), Tragus (Rt/Lt), and Zygomatic point (Rt/Lt). According to the established landmarks and measuring method, the 3D CT images of adults with normal occlusion were measured and the normal positional measurements and their Net (${\delta}=\sqrt{{X^2}+{Y^2}+{Z^2}}$) values were obtained using V surgery program, In the linear measurement between landmarks, there was a significant difference between males and females except Na' -Sn and En(Rt)-En(Lt). The normal ranges of Na'-Zy, Na'-Ch and Na'-Go' (facial depth) were obtained, which was difficult to measure by two-dimensional (2D) cephalometric analysis and facial photographs. These data may be used as references for 3D diagnosis and treatment planning for patients with malocclusion and dentofacial deformity.

The effect of repeated firings on the color of zirconia-based all-ceramic system (반복 소성이 지르코니아 전부도재관의 색조에 미치는 영향)

  • Jang, Jung-Eun;Kim, Mu-Hyon;Yun, Mi-Jung;Jeong, Chang-Mo;Jeon, Young-Chan
    • The Journal of Korean Academy of Prosthodontics
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    • v.49 no.1
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    • pp.73-79
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    • 2011
  • Purpose: The aim of this study was to evaluate the effect of repeated firings on the color of zirconia restoration with different shading method. Materials and methods: Three different types of zirconia frameworks (adding metallic pigments to the initial zirconia powder before sintering (Group NM), dipping the milled frameworks in dissolved coloring agents (Group KI), or application of liner material to the sintered white frameworks (Group KW) were used to support A3 shade dentin porcelain. Repeated firings (3, 5, or 7) were performed, color differences among ceramic specimens were measured using a colorimeter. Repeated measurements analysis of variance (ANOVA) was used to analyze the data for significant difference. The Tukey Honestly Significant Different (HSD) test was used to perform multiple comparisons (${\alpha}$ = .05). Results: 1. $L^*a^*b^*$ values of the ceramic systems were affected by the number of firings (1, 3, 5 or 7 firings) (P < .001) and shading methods (P < .001). 2. As the number of firings increased, the $L^*$ (for all groups) and $a^*$ value (for KW and NM groups) decreased and the $b^*$ value(for all groups) increased. 3. The mean color differences caused by repeated firings were perceptible (${\Delta}E$ > 1) for group KW and KI fired after 3 times, except for group NM fired after 7 times. 4. In order of decreasing ${\Delta}E$ value fired after 7 times, the values were group KI(${\Delta}E$ = 2.26) > group KW (${\Delta}E$ = 1.47) > group NM (${\Delta}E$ = 1.08) (P < .001). Conclusion: Repeated firings influenced the color of the zirconium-oxide all-ceramic specimens with different shading methods.

AGE ESTIMATION USING PANORAMIC RADIOGRAPHS OF DEVELOPING PERMANENT TEETH (발육중인 영구치의 파노라마 방사선 사진 계측을 이용한 연령 추정)

  • Choi, Eun-Young;Choi, Nam-Ki;Kim, Seon-Mi;Yang, Kyu-Ho
    • Journal of the korean academy of Pediatric Dentistry
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    • v.34 no.2
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    • pp.215-221
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    • 2007
  • The aim of this study was to test whether metric measurements of crown length, root length and apex width during tooth development could be a better basis for correlation with age than the classical methods based on subjective estimations of various stages of tooth development. Panoramic radiographs of 120 children, aged 7 to 9 years, were collected from the department of the pediatric dentistry of Chonnam National University Hospital, Korea. The methods of Mornstad was used to estimate age. The structures measured were crown length root length and apex width in panoramic radiographic. The results were as follows : 1. In the boys, it showed higher correlation between lower 2nd molar crown length, lower 1st molar root length or lower 1st permolar apical width and age. In the girls, it showed higher correlation between lower 2nd premolar crown length, lower 2nd molar root length or lower 1st molar apical width and age. 2. With the aid of a multiple regression model, a linear relationship between some of these distances and age was shown. Boy(months) = 43.958 + lower 2nd molar crown length ${\times}$ 4.392 + lower 1st molar root length ${\times}$ 2.255 - lower 1st permolar apical width ${\times}$ 2.046, Girl(months) = 75.213 + lower 2nd premolar crown length ${\times}$ 3.910 lower 2nd molar root length ${\times}$ 2.280 - lower 1st molar apical width ${\times}$ 6.217 Age was estimated in boys and girls using the mathematic model ; the mean difference between chronological and estimated ages was $-2.1{\pm}6.8$ months for boys and $6.1{\pm}6.2$ months for girls. Therefore, it seems to be more accurate and easier than the earlier methods.

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