• Title/Summary/Keyword: Mass profile

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High-resolution mass models of the Large Magellanic Cloud

  • Kim, Shinna;Oh, Se-Heon;For, Bi-Qing;Sheen, Yun-Kyeong
    • The Bulletin of The Korean Astronomical Society
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    • v.46 no.2
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    • pp.71.1-71.1
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    • 2021
  • We perform disk-halo decomposition of the Large Magellanic Cloud (LMC) using a novel HI velocity field extraction method, aimed at better deriving its HI kinematics and thus mass distribution in the galaxy including both baryons and dark matter. We decompose all the line-of-sight velocity profiles of the combined HI data cube of the LMC, taken from the Australia Telescope Compact Array (ATCA) and Parkes radio telescopes with an optimal number of Gaussian components. For this, we use a novel tool, the so-called BAYGAUD which performs profile decomposition based on Bayesian MCMC techniques. From this, we disentangle turbulent non-ordered HI gas motions from the decomposed gas components, and produce an HI bulk velocity field which better follows the global circular rotation of the galaxy. From a 2D tilted-ring analysis of the HI bulk velocity field, we derive the rotation curve of the LMC after correcting for its transverse, nutation and precession motions. The dynamical contributions of baryons like stars and gaseous components which are derived using the Spitzer 3.6 micron image and the HI data are then subtracted from the total kinematics of the LMC. Here, we present the bulk HI rotation curve, the mass models of stars and gaseous components, and the resulting dark matter density profile of the LMC.

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Distribution of Baryonic Matter in Dark Matter Halos: Effect of Dynamical Friction

  • Bae, Yeong-Bok;Lee, Hyung-Mok
    • The Bulletin of The Korean Astronomical Society
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    • v.36 no.1
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    • pp.47.1-47.1
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    • 2011
  • We studied the evolution of the two mass components system with NFW initial density distribution by direct integration of the Fokker-Planck equations. The low mass component is regarded the dark matter particles while the high mass component is assumed to be conglomerates of baryonic matter in order to depict the 'stars'. While the true mass ratio between these two types of particles should be extremely large, our adopted mass ratio is about 1000 beyond which the dynamical evolution and density distribution tend to converge. Since the dynamical evolution is dominated by the dynamical friction, the high mass component slowly moves toward the central part, and eventually undergoes the core collapse. The system reaches the core-collapse at about $7.1{\times}10^{-3}$ $t_{fh}$ in NFW models, where $t_{fh}$is the dynamical friction time at half-mass radius. The distribution of the high mass component is well fitted by the Sersic profiles or modified Hubble profile when the mass segregation is established. From these results, the surface brightness of elliptical galaxies may be explained by the high mass component experiencing dynamical friction by the dark matter particles. In order for the mass segregation to be effective within Hubble time, the mass of the luminous component should be greater than $10^5M_{\bigodot}$.

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Effect of Complete Fasting on Body Fatness, Serum Leptin and Lipid Profile in Women (여성에서 절식이 체지방과 혈청의 Leptin 및 지질조성에 미치는 영향)

  • 이은옥;박현서;신현대
    • Journal of Nutrition and Health
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    • v.33 no.1
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    • pp.42-48
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    • 2000
  • The study was designed to observe the effect of complete listing for 10 days on body fatness, serum leptin level and lipid profile in thirty women who were admitted to fasting Clinical Program in Kyung-Hee Oriental Medical Center. Most of the subjects had food habits of over-eating and preferred oily foods which was correlated to the increase of body weight and BMI during realimentation. Average loss of body weight was 7.98kg and waist-hip ratio was significantly decreased during fasting. Body weight showed significant positive correlation with body fat(r=0.8182), lean body mass(r=0.7797) and total body water(r=0.7563). Body fat was gradually reduced after 9 days fasting, but lean body mass was not diminished any more after 7 days luring. Serum leptin level was significantly decreased after luring and re-feeding. The leptin showed significant positive correlation with body weight(r=0.9324), body mass index(r=0.8279) and body fat(r=0.8376). The levels of serum total cholesterol and LDL-C were significantly increased but HDL-C level was significantly decreased after fasting which increased could be harmful for persons with hypercholesterolemia. VLDL-C and triglyceride levels were not significantly decreased after fasting. Serum total free fatty acid level was significantly increased after fasting. These data suggest that the best way of maintaining the reduced body weight was to carry out the modification of food habits and behavior in daily lift. It could not be recommended to repeat often complete luting for reduction of body weight. (Korean J Nutrition 33(1) : 42-48, 2000)

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Utility of False Profile View for Screening of Ischiofemoral Impingement

  • Kwak, Dae-Kyung;Yang, Ick-Hwan;Kim, Sungjun;Lee, Sang-Chul;Park, Kwan-Kyu;Lee, Woo-Suk
    • Hip & pelvis
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    • v.30 no.4
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    • pp.219-225
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    • 2018
  • Purpose: Ischiofemoral impingement (IFI)-primarily diagnosed by magnetic resonance imaging (MRI)-is an easily overlooked disease due to its low incidence. The purpose of this study was to evaluate the usefulness of false profile view as a screening test for IFI. Materials and Methods: Fifty-eight patients diagnosed with IFI between June 2013 and July 2017 were enrolled in this retrospective study. A control group (n=58) with matching propensity scores (age, gender, and body mass index) were also included. Ischiofemoral space (IFS) was measured as the shortest distance between the lateral cortex of the ischium and the medial cortex of lesser trochanter in weight bearing hip anteroposterior (AP) view and false profile view. MRI was used to measure IFS and quadratus femoris space (QFS). The receiver operating characteristics (ROC), area under the ROC curve (AUC) and cutoff point of the IFS were measured by false profile images, and the correlation between the IFS and QFS was analyzed using the MRI scans. Results: In the false profile view and hip AP view, patients with IFI had significantly decreased IFS (P<0.01). In the false profile view, ROC AUC (0.967) was higher than in the hip AP view (0.841). Cutoff value for differential diagnosis of IFI in the false profile view was 10.3 mm (sensitivity, 88.2%; specificity, 88.4%). IFS correlated with IFS (r=0.744) QFS (0.740) in MRI and IFS (0.621) in hip AP view (P<0.01). Conclusion: IFS on false profile view can be used as a screening tool for potential IFI.

Effects of Nutrition and Exercise Education on Fat Mass and Blood Lipid Profile in Postmenopausal Obese Women (폐경 후 비만 여성의 식이 및 운동 교육이 체지방향 및 혈중지질농도에 미치는 효과)

  • Kim, Nae-Hee;Kim, Ji-Myung;Kim, Hye-Sook;Chang, Nam-Soo
    • Journal of Nutrition and Health
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    • v.40 no.2
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    • pp.162-171
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    • 2007
  • Obesity is an independent risk factor fur coronary artery disease in the postmenopausal women, which may be mediated by alteration of blood lipid metabolism. We are aimed to evaluate the effects of low energy diet, restriction of high fat foods and exercise education on weight, fat mass and blood lipid profile. Fifteen postmenopausal obese women were studied. Subjects received detailed advice about how to achieve a reduction of weight by a low-energy diet (1,200kcal), restriction of high fat food and increased exercise in every 4 wks during 8 wk. To evaluate the effectiveness for education programs, dietary fat habit and daily nutrient intakes, exercise were tested before and after intervention. Anthropometry, computerized tomography, and blood lipid profile were assessed before and after intervention. According to the nutrition education, energy intake (from 1776.1 ${\pm}$ 28.2 kcal to 1268.7 ${\pm}$ 115.2 kcal, p < 0.001) and percent of energy from fat (21.9%, p < 0.01) were significantly decreased. However, the index of nutritional quality was over 1.0. On the contrary, exercise (from 341.3 ${\pm}$ 222.1 kcal to 569.4 ${\pm}$ 309.8 kcal, p < 0.05) was increased and dietary fat habit scores (from 30.8 ${\pm}$ 5.2 to 36.1 ${\pm}$ 3.0, p < 0.01) were improved. Also, body weight (4.2%, p < 0.001), BMI (4.5%, p < 0.001), body fat mass (3.4%, p < 0.05) and waist to hip ratio (1.1%, p < 0.05) were decreased. Among abdominal fat, visceral fat (26.1%, p < 0.05) and subcutaneous fat (14.8%, p < 0.01) were decreased. But there was no difference in visceral fat to subcutaneous fat ratio. We observed HDL-cholesterol increase (11.7%, p < 0.05), triglyceride reduction(14.8%, p < 0.05) and atherogenic index improvement (from 2.7 ${\pm}$ 0.7 to 2.3 ${\pm}$ 0.7, p < 0.05) However, there was no change in LDL-cholesterol and total cholesterol. Theses results showed that low energy diet, restriction of high fat foods and exercise education could result in reduction of body weight, fat mass, visceral and subcutaneous fat, and in improvement of blood lipid profile in the postmenopausal obese women.

Experimental Study for the Identification of the Nascent Product of OH Heterogeneous Reaction with NaCl using Chemical Ionization Mass Spectrometry

  • Park, Jong-Ho;Ivanov, Andrey V.;Molina, Mario J.
    • Mass Spectrometry Letters
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    • v.3 no.4
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    • pp.108-111
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    • 2012
  • An experimental study on the nascent product of the OH heterogeneous reaction with NaCl was performed under dry and wet conditions using a bead-filled flow tube system coupled to a high-pressure chemical ionization mass spectrometer. The ozone concentration in the flow tube for the atomic hydrogen removal was varied in order to control the conversion reaction of molecular chlorine into HCl for the identification of the nascent product. The mass spectrometric observation was that the $O_3$ introduction reduced the concentration HCl, while it increased the concentration of $Cl_2$ and ClO. Based on the experimental results, we suggest that the nascent product of the titled reaction is gaseous $Cl_2$, which is followed by fast conversion into HCl in presence of H. No significant difference in the concentration profile between under dry and wet (RH = 2%) conditions was observed.

Blue profile in different evolutionary stages of massive star forming regions

  • Jin, Mihwa;Lee, Jeong-Eun;Kim, Kee-Tae
    • The Bulletin of The Korean Astronomical Society
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    • v.40 no.1
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    • pp.68.1-68.1
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    • 2015
  • Gravitational collapse is a dynamical process associated with star formation. One observational evidence of such infall motion is so called "blue asymmetry" profile, which is the optically thick line profile with the intensity peak skewed blueward relative to the intensity peak of optically thin lines. We analyzed both HCN J=1-0 and HNC J=1-0 line profiles to study the inflow motion in different evolutionary stages of massive star formation; Infrared dark clouds (IRDCs), High-mass protostellar object (HMPOs), and Ultra-compact HII regions (UCHIIs). The infall asymmetry in the HCN spectra seems to be more prevalent than the HNC spectra throughout all the three evolutionary phases. The prevalence of the blue profile in the HCN spectra is found in every evolutionary stage, with IRDCs showing the largest blue excess. In the case of the HNC spectra, only IRDCs show the blue excess statistically significant. These results suggest that HCN may be a better infall tracer in massive star forming region. In addition, even though the characteristics of the blue profile largely depend on the suitable combination of optical depth and critical density, our analyses also indicate that IRDCs may have the most active infall process compared to other evolutionary phases.

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Development of the vac Source Profile using Collinearity Test in the Yeosu Petrochemical Complex (여수석유화학산단의 공선성 시험을 이용한 VOC 오염원 분류표 개발)

  • Jeon Jun-Min;Hur Dang;Hwang In Jo;Kim Dong-Sul
    • Journal of Korean Society for Atmospheric Environment
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    • v.21 no.3
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    • pp.315-327
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    • 2005
  • The total of 35 target VOCs (volatile organic compounds), which were included in the TO-14, was selected to develop a VOCs' source profile matrix of the Yeosu Petrochemical Complex and to test its collinearity by singular value decomposition(SVD) technique. The VOCs collected in canisters were sampled from 12 different sources such as 8 direct emission sources (refinery, painting, wastewater treatment plant, incinerator, petrochemical processing, oil storage, fertilizer plant, and iron mill) and 4 general area sources (gasoline vapor emission, graphic art activity, vehicle emission, and asphalt paving activity) in this study area, and then those samples were analyzed by GC/MS. Initially the resulting raw data for each profile were scaled and normalized through several data treatment steps, and then specific VOCs showing major weight fractions were intensively reviewed and compared by introducing many other related studies. Next, all of the source profiles were tested in terms of degree of collinearity by SVD technique. The study finally could provide a proper VOCs' source profile in the study area, which can give opportunities to apply various receptor models properly including chemical mass balance (CMB).

THE EFFECTS OF WALL BOUNDARY CONDITIONS ON MASS TRANSFER IN TURBULENT PIPE FLOW (난류 파이프 유동 내 물질전달에서의 경계조건 영향)

  • Kang, Chang-Woo;Yang, Kyung-Soo
    • Journal of computational fluids engineering
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    • v.17 no.2
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    • pp.42-52
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    • 2012
  • Direct Numerical Simulation(DNS) of turbulent mass transfer in fully developed turbulent pipe flow has been performed to study the effect of wall boundary conditions on the concentration fields at $Re_{\tau}$=180 based on friction velocity and pipe radius. Fully developed turbulent pipe flows for Sc=0.71 are studied with two different wall boundary conditions, namely, constant mass flux and constant wall concentration. The mean concentration profiles and turbulent mass fluxes obtained from the present DNS are in good agreement with the previous numerical results currently available. To investigate the effects of wall boundary condition on the turbulent mass transfer, the mean concentration profile, root-mean-square of concentration fluctuation, turbulent mass fluxes and higher-order statistics(Skewness and Flatness factor) are compared for the two cases. Furthermore, the budgets of turbulent mass fluxes and concentration variance were computed and analyzed to elucidate the effects of wall boundary conditions on the turbulent mass transfer.

Effects of Obesity Educational Program on Blood Lipid Profile and Body Composition of Overweight Elementary School Students (비만교육프로그램이 과체중 초등학생들의 혈중 지질 및 신체 조성에 미치는 영향)

  • Lee, A-Ra;Song, Mi-Yeon
    • Journal of Korean Medicine for Obesity Research
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    • v.9 no.2
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    • pp.1-10
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    • 2009
  • Objectives This study was performed to find out the effects of obesity educational program on blood lipid profile and body composition on overweight elementary school students. Methods Twenty-five overweight elementary school students were recruited in 2009. Pilates exercise(9 times, twice per week), two smile theraphie, and nutrition consults were underwent for two months. Anthropometry, bioelectrical impedance analysis, and blood test have been done before and after the program. Result There were significant changes in height, weight, waist circumference, body mass index, and percent body fat after the program. Conclusion The obesity educational program which were consisted of pilates exercise, smile theraphies, and nutrition consults had effects on overweight elementary school students' losing weight and improving lipid profile.

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