• Title/Summary/Keyword: Mass loss rates

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OH, SiO and $H_2O$ maser emission in O-rich AGB stars

  • Kwon, Young-Joo;Suh, Kyung-Won
    • The Bulletin of The Korean Astronomical Society
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    • v.37 no.2
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    • pp.140.1-140.1
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    • 2012
  • We investigate properties of maser emission for 3373 O-rich AGB stars. We divide the sample stars into four different groups whether they were detected by OH, SiO and $H_2O$ maser emission or not. To understand the nature of the maser sources, we present various infrared two-color diagrams (2CDs) using IRAS, near infrared and AKARI data. For each group, we compare the positions on the various infrared 2CDs with theoretical models. We find that OH maser sources generally show higher color indices and larger dust optical depths than SiO or $H_2O$ maser sources. This could be due to differences of the mass-loss rates and/or variability which may influence the maser pumping mechanisms.

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NIR spectroscopy of three class I young stellar objects using IGRINS

  • Sharma, Neha;Lee, Joeng-Eun;Park, Sunkyung;Lee, Soekho;Yoon, Sung-Yong
    • The Bulletin of The Korean Astronomical Society
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    • v.44 no.1
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    • pp.66.3-66.3
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    • 2019
  • We present near-infrared spectroscopic results for three nearby class I sources, IRAS 03445+3242, IRAS 04239+2436 and ESO $H{\alpha}$ 279a. We detected many molecular and atomic line emissions, e.g., $H_2$, [Fe II], Hydrogen Bracket series recombination, Ca I, Na I & CO overtone band, from these sources using the high-resolution Immersion GRating INfrared Spectrometer (IGRINS; R~45,000). Previous studies showed that all the three sources posses actively accreting Keplerian disks. We performed spectral analysis to understand the origin of Hydrogen Bracket series recombination lines. We also estimated the accretion properties and mass loss rates of circumstellar disks for all the three sources.

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The Impact of Perforator Number on Deep Inferior Epigastric Perforator Flap Breast Reconstruction

  • Grover, Ritwik;Nelson, Jonas A.;Fischer, John P.;Kovach, Stephen J.;Serletti, Joseph M.;Wu, Liza C.
    • Archives of Plastic Surgery
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    • v.41 no.1
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    • pp.63-70
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    • 2014
  • Background Perforator flaps minimize abdominal site morbidity during autologous breast reconstruction. The purpose of this study was to assess whether the number of perforators harvested influences the overall deep inferior epigastric perforator (DIEP) flap survival and flap-related complications. Methods A retrospective review was performed of all DIEP flaps performed at the Hospital of the University of Pennsylvania from 2006 to 2011. The outcomes assessed included flap loss and major complications. We compared flaps by the number of total perforators (1-4) and then carried out a subgroup analysis comparing flaps with one perforator to flaps with multiple perforators. Lastly, we conducted a post-hoc analysis based on body mass index (BMI) categorization. Results Three hundred thirty-three patients underwent 395 DIEP flaps. No significant differences were noted in the flap loss rate or the overall complications across perforator groups. However, the subgroup analysis revealed significantly higher rates of fat necrosis in the case of one-perforator flaps than in the case of multiple-perforator flaps (10.2% vs. 3.1%, P=0.009). The post-hoc analysis revealed a significant increase in the flap loss rate with increasing BMI (<30=2.0%, 30-34.9=3.1%, 35-39.9=3.1%, >40=42.9%, P<0.001) in the DIEP flaps, but no increase in fat necrosis. Conclusions This study demonstrates that the number of perforators does not impact the rate of flap survival. However, the rate of fat necrosis may be significantly higher in DIEP flaps based on a single perforator. Multiple perforators should be utilized if possible to decrease the risk of fat necrosis.

Clinical Prognostic Factors and Survival Outcome in Renal Cell Carcinoma Patients - A Malaysian Single Centre Perspective

  • Yap, Ning Yi;Ng, Keng Lim;Ong, Teng Aik;Pailoor, Jayalakshmi;Gobe, Glenda Carolyn;Ooi, Chong Chien;Razack, Azed Hassan;Dublin, Norman;Morais, Christudas;Rajandram, Retnagowri
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.12
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    • pp.7497-7500
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    • 2013
  • Background: This study concerns clinical characteristics and survival of renal cell carcinoma (RCC) patients in University Malaya Medical Centre (UMMC), as well as the prognostic significance of presenting symptoms. Materials and Methods: The clinical characteristics, presenting symptoms and survival of RCC patients (n=151) treated at UMMC from 2003-2012 were analysed. Symptoms evaluated were macrohaematuria, flank pain, palpable abdominal mass, fever, lethargy, loss of weight, anaemia, elevated ALP, hypoalbuminemia and thrombocytosis. Univariate and multivariate Cox regression analyses were performed to determine the prognostic significance of these presenting symptoms. Kaplan Meier and log rank tests were employed for survival analysis. Results: The 2002 TNM staging was a prognostic factor (p<0.001) but Fuhrman grading was not significantly correlated with survival (p=0.088). At presentation, 76.8% of the patients were symptomatic. Generally, symptomatic tumours had a worse survival prognosis compared to asymptomatic cases (p=0.009; HR 4.74). All symptoms significantly affect disease specific survival except frank haematuria and loin pain on univariate Cox regression analysis. On multivariate analysis adjusted for stage, only clinically palpable abdominal mass remained statistically significant (p=0.027). The mean tumour size of palpable abdominal masses, $9.5{\pm}4.3cm$, was larger than non palpable masses, $5.3{\pm}2.7cm$ (p<0.001). Conclusions: This is the first report which includes survival information of RCC patients from Malaysia. Here the TNM stage and a palpable abdominal mass were independent predictors for survival. Further investigations using a multicentre cohort to analyse mortality and survival rates may aid in improving management of these patients.

Analytical Methods of Leakage Rate Estimation from a Containment tinder a LOCA (냉각수상실 사고시 격납용기로부터 누출되는 유체유량 추산을 위한 해석적 방법)

  • Moon-Hyun Chun
    • Nuclear Engineering and Technology
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    • v.13 no.3
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    • pp.121-129
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    • 1981
  • Three most outstanding maximum flow rate formulas are identified from many existing models. Outlines of the three limiting mass flow rate models are given along with computational procedures to estimate approximate amount of fission products released from a containment to environment for a given characteristic hole size for containment-isolation failure and containment pressure and temperature under a loss of coolant accident. Sample calculations are performed using the critical ideal gas flow rate model and the Moody's graphs for the maximum two-phase flow rates, and the results are compared with the values obtained from the mass leakage rate formula of CONTEMPT-LT code for converging nozzle and sonic flow. It is shown that the critical ideal gas flow rate formula gives almost comparable results as one can obtain from the Moody's model. It is also found that a more conservative approach to estimate leakage rate from a containment under a LOCA is to use the maximum ideal gas flow rate equation rather than tile mass leakage rate formula of CONTEMPT-LT.

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Diet and Metabolic Disease Risk Related to Sarcopenia in Pre- and Postmenopausal Adult Women: Based on the Korea National Health and Nutrition Examination Survey (2009-2011) (폐경 전·후 성인 여성에서 근감소증과 관련된 식생활 요인 및 대사성 질환 위험도: 국민건강영양조사(2009-2011) 자료를 활용하여)

  • Kim, Mi Hyun
    • Journal of the Korean Society of Food Culture
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    • v.36 no.4
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    • pp.401-411
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    • 2021
  • Diet is important for muscle health and offers a protective effects against the loss of skeletal muscle mass and physical functions with advancing age. We analyzed the relationship between diet, metabolic disease risk, and sarcopenia in Korean female adults using the 2009-2011 Korea National Health and Nutrition Examination Survey (KNHANES). A total of 2038 adult women aged 50-64 years were classified into four groups based on the diagnosis of menopause and sarcopenia. The groups were the non-menopause and non-sarcopenia group (NMNS, n=249), the non-menopause and sarcopenia group (NMS, n=14), the menopause and non-sarcopenia group (MNS, n=1,653), and the menopause and sarcopenia group (MS, n=122). The socio-demographics, anthropometrics, blood profile, and dietary data of the subjects were collected. Those who were in both the sarcopenia groups were more obese (p<0.001), had greater waist circumferences (p<0.001), higher body mass index (p<0.001), and higher obesity rates (p<0.001) after adjustment for covariants. Both the sarcopenia groups also had higher plasma levels of total cholesterol (p<0.001), HbA1c (p=0.001), and vitamin D (p=0.020) than both the non-sarcopenia groups. Both the sarcopenia groups demonstrated a decreased intake of calcium (p=0.05), potassium (p=0.008), and niacin (p=0.008) than both the non-sarcopenia ones. Among the four groups, the NMS group showed the highest levels of total cholesterol, obesity, and lowest intake of micronutrients such as calcium, niacin, and potassium. Thus, muscle mass maintenance through weight control and adequate nutrient intake appears to demonstrate a potential association with preventing sarcopenia in Korean middle-aged women.

The Characteristics of Oxygen Deficient Water Mass in Gamak Bay (가막만 빈산소 수괴의 특성)

  • Kim, Jeong-Bae;Lee, Sang-Yong;Yu, Jun;Choi, Yang-Ho;Jung, Chang-Su;Lee, Pil-Yong
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.9 no.4
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    • pp.216-224
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    • 2006
  • To clarify the formation process and characteristics of oxygen deficient water mass in Gamak Bay, oxygen deficiency was weekly observed from 17 June to 12 September 2005. Surface water temperature was significantly lower in the outer bay than in the inner bay, whereas the bottom water temperature was higher in the central area of bay than in the outer and inner bay. The vertical stratification of water mass was strongly formed during the period, and thermocline was observed between 3 and 5m deep. The oxygen deficiency in the bottom layer began to appear at early July in the inner bay and gradually spread to the center area of the bay in early August. The mean transparency and light attenuation coefficient($K_d$) in water mass was 4.0m and 0.47, respectively. Average concentrations of nutrient and chlorophyll ${\alpha}$ in the bottom layer were significantly higher than those in surface, and those concentrations were significantly higher in the inner bay than in the outer bay. During the formation of oxygen deficiency in the bottom layer, oxygen penetration depth in the bottom sediment were extremely shallow, and oxygen consumption rate in the bottom sediment were lower than that in the area where oxygen deficient water mass disappeared. Dissolved oxygen concentrations in the bottom layer are negatively correlated with nutrient concentrations, whereas those in the surface layer did not show a significant relationship with nutrient concentrations. Elevated loss of oxygen in the bottom water mass was attributed to the increase of the oxygen consumption rates in sediments and the decomposition of organic matter by microorganism.

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Effects of Canopy Removal on Cellulose Decomposition and Nitrogen Mineralization in Quercus rubra Stands (임관 제거가 루브라참나무림의 셀룰로오스 분해와 질소 무기화에 미치는 영향)

  • Kim, Choonsig
    • The Korean Journal of Ecology
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    • v.18 no.2
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    • pp.219-230
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    • 1995
  • Although many studies of nutrient cycling in forest ecosystems have reported that clearcutting creates increased organic matter decomposition and nitrogen (N) mineralization in soils, little is known about the change of these factors following various levels of canopy removal. A series of experimental plots with four levels of canopy cover, i.e., clearcut, 25%, 75%, and uncut, was established in northern red oak (Quercus rubra L.) stands in northern Lover Michigan, U.S.A. I examined decomposition of cellulose filter papers and N mineralization using an in situ soil incubation technique in the top 15cm of mineral soil during the second growing season (1992, May-October) following stand manipulation. Mass loss from cellulose filter papers was more rapid in the canopy removal treatments than in the uncut treatment. similarly, net N mineralization was significantly greater in the canopy removal treatments than in the uncut treatment. There was no significant difference in net N mineralization rates among the three levels of canopy removal. Net N mineralization for the growing season was 58 kg/ha for the clearcut, 54 kg/ha for the 25% canopy cover, 51 kg/ha for the 75% canopy cover, and 22 kg/ha for the uncut treatment. These results indicated that even only small amounts of canopy removal (leaving 75% canopy cover) let to substantial increases of cellulose decomposition and the amount of available soil nitrogen.

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A Study on the Leakage Interception Work in the Irrigation Canal Founding on the Sandy Gravel or the Porous Soil (모래자갈과 누수성 토질을 기반으로하는 용수로의 누수방지에 대한 연구)

  • 강신업
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.12 no.2
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    • pp.1965-1970
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    • 1970
  • The experiment was carried out in order to improve the leakage stopping work in the irrigation canal founding on the porous soil. But the experiment had many problems to be studied more owing to the insufficient time and facilities. The results obtained are summarized as follows; 1. Polyethylene film is estimated not to make strength decrease owing to buring in the subsoil, but to make owing to the sunlight. 2. Coated nylon shows the tendency to deteriorate strength when it is buried in the earth or exposed to the sun for long time, but leakage is all but impermeability generally. 3. Leakage loss rates for one hour show some differences in the canal to be full with water in accordance with operating methods, that is, the clay lining section is 12.6%, the coated nylon lining section is 1.7%, the polyethylene film lining section is 1.3%, respectively. 4. Leakage quantities per wetted perimeter unit area show $3.556cc/cm^2/hr$. in the clay lining section, $1.574cc/cm^2/hr$. in the coated nylon section, $0.695cc/cm^2/hr$. in the polyethylene film lining section, respectively. 5. When the construction fund make the clay lining section as a standard, the polyethylene film section is 92.1%, the coated nylon section is 174.2%, respectively. But, the unit cost of execution may be low when the polyethylene film and the coated nylon will enable to mass-produce for the purpose of execution.

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Seasonal Difference in Macroinvertebrate Contribution to the Leaf Litter Breakdown in a Headwater Stream at Mt. Jumbong (점봉산 소하천의 낙엽분쇄에 대한 대형무척추동물 기여도의 계정간 차이)

  • Chung, Keun
    • The Korean Journal of Ecology
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    • v.19 no.6
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    • pp.563-573
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    • 1996
  • Macroinvertebrate contribution to the leaf litter breakdown of Carpinus cordata was estimated at headwater streams at Mt. Jumbong (38°03'N, 128°25'E) during spring and winter spring by using two types of litter bag. Coarse-mesh bags with 10 g of leaf letter were placed in a 1st-order stream in April (the spring experiment) and December 1995 (the winter-spring experiment). Fine-mesh bags with 5 g of leaf letter were placed in a nearby 3ed-order steam. The breakdown of Carpinus in coarse-mesh bags was rapid, and, in terms of season, leaf litter processed rapidly during spring. daily mass loss rates of leaf litter (-k±1 SE) were highest for coarse-mesh bags in the spring experiment (-0.0429±0.0048), followed by coarse-mesh bags in the winter-spring (-0.0146±0.0014), fine-mesh bags in the spring (-0.0078±0.0004), fine-mesh bags in the winter-spring experiment (-0.0054±0.0005). Macroinvertebrate contribution to the litter breakdown was estimated by the difference of % leaf letter remaining between coarse -mesh bage and fine-mesh bags. Although shredders were more abundant during the winter-spring, their contribution was greater during the spring (50%) than the winter-spring (22∼33%). This result appeared to be due to the change in the chemical composition of leaf letter during processing, and to the seasonal growth patterns of major shredder taxa.

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