• Title/Summary/Keyword: $^{234}Th$

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Estimation of the Spring and Summer Net Community Production in the Ulleung Basin using Machine Learning Methods (기계학습법을 이용한 동해 울릉분지의 봄과 여름 순군집생산 추정)

  • DOSHIK HAHM;INHEE LEE;MINKI CHOO
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.29 no.1
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    • pp.1-13
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    • 2024
  • The southwestern part of the East Sea is known to have a high primary productivity compared to those in the northern and eastern parts, which is attributed to nutrients supplies either by Tsushima Warm Current or by coastal upwelling. However, research on the biological pump in this area is limited. We developed machine learning models to estimate net community production (NCP), a measure of biological pump, with high spatial and time scales of 4 km and 8 days, respectively. The models were fed with the input parameters of sea surface temperature, chlorophyll-a, mixed layer depths, and photosynthetically active radiation and trained with observed NCP derived from high resolution measurements of surface O2/Ar. The root mean square error between the predicted values by the best performing machine model and the observed NCP was 6 mmol O2 m-2 d-1, corresponding to 15% of the average of observed NCP. The NCP in the central part of the Ulleung Basin was highest in March at 49 mmol O2 m-2 d-1 and lowest in June and July at 18 mmol O2 m-2 d-1. These seasonal variations were similar to the vertical nitrate flux based on the 3He gas exchange rate and to the particulate organic carbon flux estimated by the 234Th disequilibrium method. To expand this method, which produces NCP estimate for spring and summer, to autumn and winter, it is necessary to devise a way to correct bias in NCP by the entrainment of subsurface waters during the seasons.

A CLINICOSTATISTICAL STUDY ON MIDFACIAL BONE FRACTURE (중안면골 골절에 대한 임상통계학적 연구)

  • Ryu, Sun-Youl;Cho, Kyu-Seung
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.19 no.4
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    • pp.367-376
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    • 1997
  • The 234 patients who received treatment of midfacial fractures at the Department of Oral and Maxillofacial Surgery of Chonnam University Hospital from Jan. 1, 1992 to Dec. 31, 1996 were analyzed clinicostastically. Results obtained were as follows ; Male predominated over females by a ratio of 5.3 to 1. The frequently developing age groups were first 3rd (25%), 4th (21%) and the 2nd (18%) decade on succession. The peakest month was the August (16%), and May (11%), September (9%), October (9%). When it comes to the reasons for in-patients, traffic accident was predominant to 38%. In the 234 cases of midfacial fractures, zygomaticomaxillary complex fracture was the most by 37%. The most common with injury show that facial laceration marked by 49%, neurologic injury 24%, and mandibular fracture 20% each by each. About the time from injury onset to operation, 55% of cases were less than a week while the others (45%) more than a week. 3 plates were used for operation : 2 for zygoma or maxilla fracture and 3 for zygomatiomaxillary complex fracture. especially 4 for Le Fort I fracture, 5.5 for Le Fort I, II ; I, III ; II, III fracture, 7 for Le Fort I,II,III fracture were used. 20 patients (8%) appealed their complication and the most common was reported as infection. Above results suggest that early diagnosis and treatment of fracture site, systemic condition and associated injuries are necessary, and coorperative treatment with medical department should be performed.

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A study on TMD and stress of first children (첫째 아이의 스트레스와 측두하악장애에 관한 연구 - 고등학생을 중심으로 -)

  • Kim, Myung-Eun
    • Journal of Korean society of Dental Hygiene
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    • v.10 no.4
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    • pp.683-693
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    • 2010
  • Objectives : The purpose of this study was to examine the relation between stress and temporomandibular disorder(TMD) of first the child. Methods : 500(the first child -250, non first child -250) high school students living in Jecheon city, form November 4th to 5th 2009, were the subjects of this questionnaire. The questionnaire was made up of three contests: sociodemographic characteristic, symptom & dysfunction of TMD and stress of high school students. The data were analyzed by chi-square test, two sample t-test and Pearson correlation. Results : Only 443(the first child -209, non first child - 234) students were evaluated due to inadequate responses. The obtain results was as follow. 1. Subjective symptom of TMD reported by 443 students were joint sound(63.5%), pain on chewing(55.1%), pain on opening the mouth(55.1%). 2. Analysis of subjective symptom of TMD showed the first child group was statistical significantly higher on joint sounds and TMJ pain than non first child group(<0.05). 3. Analysis of bad habit and dysfunction showed the first child group was statistical significantly higher on clenching of the teeth, difficulties of bite, headache than non first child group(<0.05). 4. Analysis of stress showed the first child group was statistical significantly higher on stress with parents than non first child. especially on marks and disagreement(<0.05). 5. Stress were partly related to subject symptom of TMD(<0.05, <0.01). 6. Analysis of relation stress and bad habit & dysfunction showed stress were partly related to bad habit & dysfunction(<0.05, <0.01). 7. bad habit were partly related to TMD(<0.05, <0.01). Conclusions : The first child stress and symptom of TMD were higher than non-first child, also stress and symptom of TMD was positively associated. therefore management of the first child' stress is necessary and related study is necessary in the future.

Distribution of Radon Concentration at Subway Station in Seoul (서울시 지하철역사의 라돈농도분포 조사)

  • Lee Cheol-Min;Kim Yoon-Shin;Kim Jong-Cheol;Jeon Hyung-Jin
    • Journal of Environmental Health Sciences
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    • v.30 no.5 s.81
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    • pp.469-480
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    • 2004
  • The radon concentrations were measured to survey distribution of radon concentrations in Seoul subway stations. The radon concentrations in air and water were measured at seventeen subway stations(Mapo, Chungjongno, Sodaemun, Kwanghwamun, Chongno3ga, Ulchiro4ga, Tangdaemun, Sangildong on Line 5;Nowon, Chunggye, Hagye, Kongnung, Taenung, Mokkol, Chunghwa, Sangbong, Myomok on Line 7) using the $RAdtrak^{TM}$ radon gas detector, Pylon AB-5 continuous passive radon detector and liquid scintillation counting method from January to May 1999. The major results obtained from this study were as follows: The long-term mean concentrations of radon were $61.8\;Bq/m^3$ in office, $78.9\;Bq/m^3$ in platform, $38.2\;Bq/m^3$ in concourse and $20.1\;Bq/m^3$ in outdoor, respectively. These levels were less than the action level ($148\;Bq/m^3$) of the U.S. EPA. The highest level of short-term mean concentrations was $116.55\;Bq/m^3$ at Chongno3ga station on the 5th line subway stations, while the lowest mean concentration was $19.55\;Bq/m^3$ at Mokkol station on the 7th line subway stations. The highest concentration of radon in the road water and storing underground water in the subway stations was $234.7\;KBq/m^3\;and\;155.5\;KBq/m^3$ in Sodaemun subway station, respectively. The results suggest that radon concentration in subway stations seems to be affected by ventilation and radon concentratin in underground water in the subway stations.

Study of Traditional Plants of Jeju Island (Five literatures in Joseon Dynasty period) (조선시대 문헌에 기록된 제주도 전통식물의 통시적 연구-세종실록지리지, 신증동국여지승람, 탐라지, 남환박물, 제주계록을 중심으로-)

  • Lee, Chang Shook;Yeau, Sung Hee;Chung, So Yeon
    • Korean Journal of Plant Resources
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    • v.29 no.2
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    • pp.225-234
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    • 2016
  • To understand the traditional knowledge of botanical taxa in Jeju Island, a diachronic study was carried out by comparing the archaic and modern names of the native plants in Jeju Island. To identify the archaic names of the plants, five old documents (Sejongshillokchiriji, Shinjŭngdonggukyŏjisŭngnam, T'amnaji, Namhwanbangmul and Jejugyerok) that were written during the Joseon Dynasty between the 15th and 19th centuries were closely examined. A total of 131 taxa (65 families, 112 genera, 118 species and 13 varieties), 7.3% of the native plants known to be currently present in Jeju Island, was identified. Out of these, 21.4% was the plants found in the southern area. Among the five old documents analyzed for this study, Namhwanbangmul recorded the largest number of plants, 89 taxa. We closely examined the consistency between the modern and archaic names of each plant, and discussed the problems in matching the names of some plants analyzed in this study.

Health Perception, Health Status and Health Promotion Behaviors of Elementary School Teacher (초등학교 교사의 건강지각, 건강상태와 건강증진행위)

  • Jung, Su Hui;Kim, Dong-Hee
    • Journal of the Korean Society of School Health
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    • v.30 no.3
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    • pp.355-364
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    • 2017
  • Purpose: The purpose of this study was to identify health promotion behaviors of elementary school teachers and investigate the factors influencing the health promotion behaviors. Methods: Data were collected from 234 elementary school teachers in the B Metropolitan City Office of Education from 5th to 30th October, 2016. The collected data were analyzed by descriptive statistics, t-test, ANOVA, $Scheff{\acute{e}}$ test, Mann-Whitney test, Kruskal-Wallis test, Spearman correlation coefficient and multiple regression analysis, using SPSS/WIN 23.0. Results: The elementary school teachers' health perception scored 2.94 out of 4, health status 1.59 out of 3, and health promotion behaviors 2.66 out of 4. The level of mental health status (1.67) was higher than that of physical health status (1.54) and the most practiced health promotion behavior was spiritual growth (3.15) and the least was health responsibility (2.00). Significant negative correlations were found between health perception and health status (r=-.59, p<.001) and between health status and health promotion behaviors (r=-.41, p<.001). A significant positive correlation was found between health perception and health promotion behaviors (r=.32, p<.001). The significant factors influencing health promotion behaviors were job stress and health status. These factors explained 19.6% of the health promotion behaviors. Conclusion: It is necessary to establish measures to increase the health perception and health promotion behaviors of elementary school teachers and improve their health status. In addition, since job stress and health status are factors influencing health promotion behaviors, it is necessary to actively manage job stress and health status in order to increase health promotion behaviors.

The effect of overweight on the luteinizing hormone level after gonadorelin stimulation test in girls with idiopathic central precocious puberty

  • Lee, Hyun Young;Lee, Yoon-Ji;Ahn, Moon-Bae;Cho, Won-Kyoung;Suh, Byung-Kyu
    • Annals of Pediatric Endocrinology and Metabolism
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    • v.23 no.4
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    • pp.215-219
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    • 2018
  • Purpose: We investigated the effect of overweight on luteinizing hormone (LH) levels after a gonadorelin stimulation test in Korean girls with idiopathic central precocious puberty (CPP). Methods: Medical records of 234 girls diagnosed with idiopathic CPP were reviewed retrospectively. CPP was diagnosed when the peak LH levels after gonadorelin stimulation was >5.0 U/L. The enrolled girls had a peak LH level >5.0 U/L after a gonadorelin stimulation test. Selected girls were classified as normoweight (body mass index [BMI] below the 85th percentile with respect to age) and overweight (BMI greater than the 85th percentile with respect to age). Results: The peak LH ($8.95{\pm}2.85U/L$ vs. $11.97{\pm}8.42U/L$, P<0.01) and peak folliclestimulating hormone ($9.60{\pm}2.91U/L$ vs. $11.17{\pm}7.77U/L$, P=0.04) after gonadorelin stimulation were lower in overweight girls with idiopathic CPP than in normoweight girls with idiopathic CPP. Being overweight was negatively associated with peak LH levels after gonadorelin stimulation test (odds ratio, 0.89; 95 % confidence interval, 0.81-0.98, P=0.02). Conclusion: In girls with idiopathic CPP, being overweight led to a lower LH peak after gonadorelin stimulation. Further research is needed to better understand the role of overweight on gonadotropin secretion in precocious puberty.

Neuroprotective Effect of β-Lapachone in MPTP-Induced Parkinson's Disease Mouse Model: Involvement of Astroglial p-AMPK/Nrf2/HO-1 Signaling Pathways

  • Park, Jin-Sun;Leem, Yea-Hyun;Park, Jung-Eun;Kim, Do-Yeon;Kim, Hee-Sun
    • Biomolecules & Therapeutics
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    • v.27 no.2
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    • pp.178-184
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    • 2019
  • Parkinson's disease is a neurodegenerative disease characterized by the progressive loss of dopaminergic neurons within the substantia nigra pars compacta. In the present study, we investigated whether ${\beta}-Lapachone$ (${\beta}-LAP$), a natural naphthoquinone compound isolated from the lapacho tree (Tabebuia avellanedae), elicits neuroprotective effects in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinson's disease mouse model. ${\beta}-LAP$ reduced the tyrosine hydroxylase (TH)-immunoreactive fiber loss induced by MPTP in the dorsolateral striatum, and alleviated motor dysfunction as determined by the rotarod test. In addition, ${\beta}-LAP$ protected against MPTP-induced loss of TH positive neurons, and upregulated B-cell lymphoma 2 protein (Bcl-2) expression in the substantia nigra. Based on previous reports on the neuroprotective role of nuclear factor-E2-related factor-2 (Nrf2) in neurodegenerative diseases, we investigated whether ${\beta}-LAP$ induces upregulation of the Nrf2-hemeoxygenae-1 (HO-1) signaling pathway molecules in MPTP-injected mouse brains. Western blot and immunohistochemical analyses indicated that ${\beta}-LAP$ increased HO-1 expression in glial fibrillary acidic protein-positive astrocytes. Moreover, ${\beta}-LAP$ increased the nuclear translocation and DNA binding activity of Nrf2, and the phosphorylation of upstream adenosine monophosphate-activated protein kinase (AMPK). ${\beta}-LAP$ also increased the localization of p-AMPK and Nrf2 in astrocytes. Collectively, our data suggest that ${\beta}-LAP$ exerts neuroprotective effect in MPTP-injected mice by upregulating the p-AMPK/Nrf2/HO-1 signaling pathways in astrocytes.

THE EFFECTS OF IRRADIATION ON THE PERIODONTAL TISSUES OF RATS WITH THE LOW CALCIUM DIET (방사선조사가 저칼슘식이 백서 치주조직에 미치는 영향에 관한 연구)

  • Choi Mun-Cheol;Lee Sang-Rae
    • Journal of Korean Academy of Oral and Maxillofacial Radiology
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    • v.22 no.2
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    • pp.223-234
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    • 1992
  • The purpose of this study was to investigate the changes of periodontal tissues in the irradiated mandibular bone in rats which were fed normal diet and low calcium diet In order to carry out this experiment, 64 seven-week old Sprague-Dawley strain rats weighing about 150gms were selected and equally divided into one experimental group of 32 rats and one control group with the remainder. The experimental group and the control group were then subdivided into two groups when the rats reached the age of 10 weeks, 16 rats were allotted for each subdivided group was composed of 16 rats and exposed to irradiation. The two groups were irradiated a single dose of 20Gy on the only jaw area and irradiated with a cobalt-60 teletherapy unit The rats in the control and experimental groups were serially dissected by fours on the 3rd, the 7th, the 14th, and the 21st day after irradiation. After each dissection, both sides of the dead rat mandibular bodies were removed and fixed with 10% neutral formalin. The specimens sectioned and observed in histopathological. histochemical. and immunocellular chemical methods. The obtained results were as follows: 1. In the mandibles of rats with low calcium diet the increased number of fibroblasts of periodontal ligaments. many small capillaries and irregular arrangement of loose collagen fibers were detected and the partial resorption of dentin and cementum could be found by the microscopic studies. 2. In the group of irradiated rats, degenerated periodontal tissues led to the condition of irregular arrangement of collagen fibers and the decreased number of fibroblasts. But this condition was somewhat restored after 21 days of experiment. 3. Periodontal tissues of the irradiated rat group with low calcium diet were destroyed earlier than those of the irradiated rat group with normal diet. Soon this condition was restored and then high cellularity and dense collagen fibers were observed. 4. Many periodontal cells bearing tumor necrosis factor could be clearly observed in the nonirradiated group of rats with normal diet, whereas could not be observed on the 7th day and reappeared on 14th day in the irradiated group of rats with normal diet. A few of them could be observed in the group of rats with low calcium diet, but they could be clearly observed in the both groups after 21 days of experiment.

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Estimation of POC Export Fluxes Using 234Th/238U Disequilibria in the Amundsen Sea, Antarctica; Preliminary Result (남극 아문젠해에서 234Th/238U 비평형법을 사용한 유광대에서 심층으로의 입자상 유기탄소 침강플럭스 추정; 예비결과)

  • Kim, Mi Seon;Choi, Man Sik;Lee, Sang Heon;Lee, Sang Hoon;Rhee, Tae Siek;Hahm, Doshik
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.19 no.2
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    • pp.109-124
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    • 2014
  • In order to understand the carbon cycle in the Amundsen Sea of the Southern Ocean, the export fluxes of particulate organic carbon from the euphotic zone to deep water estimated using ${\psi}$/${\psi}$ disequilibrium method. Seawaters in 14 water columns were collected during February and March 2012, and analyzed for total and dissolved ${\psi}$, and particulate organic carbon. Total ${\psi}$ activities in the water column showed deficiency and excess relative to those of ${\psi}$ depending on the water depth. Deficiency of total ${\psi}$ in the euphotic zone showed mirror images both with chlorophyll-a and fluorescence, and was consistent with the loss of nitrate, which indicated the effect of biological activity. In addition, deficiency of total ${\psi}$ from deep water was associated with the increase of total dissolvable Fe/Mn concentration. Excess total ${\psi}$ activity presented below the euphotic zone might be related to particulate ${\psi}$ concentrated in this water depth. Mean export flux of ${\psi}$ estimated using the steady state model was $867{\pm}246dpmm^{-2}day^{-1}$. Mean export flux of particulate organic carbon, which were estimated by the product of total ${\psi}$ flux and ratio of POC/${\psi}$ ($7.08{\pm}4.27{\mu}molCdpm^{-1}$) in the sinking particles, was $5.9{\pm}3.9mmolCm^{-2}day^{-1}$. These fluxes were similar levels to those in the Weddell Sea during February and March 2008. Export ratios (ThE) relative to the primary production in the euphotic zone were in the range of 3-54% (av. 28%).