The rotation curve of DDO 154 - A particularly acute test of the modified dynamics

1988 ◽  
Vol 334 ◽  
pp. 130 ◽  
Author(s):  
Mordehai Milgrom ◽  
Erez Braun
Keyword(s):  
Rotation Curve ◽  
Acute Test ◽  
Modified Dynamics

scholarly journals Comparison of Joint Effect of Acute and Chronic Toxicity for Combined Assessment of Heavy Metals on Photobacterium sp.NAA-MIE

2021 ◽  
Vol 18 (12) ◽  
pp. 6644
Author(s):  
Nur Adila Adnan ◽  
Mohd Izuan Effendi Halmi ◽  
Siti Salwa Abd Gani ◽  
Uswatun Hasanah Zaidan ◽  
Mohd Yunus Abd Shukor
Keyword(s):  
Heavy Metals ◽  
Chronic Toxicity ◽  
Mixture Toxicity ◽  
Joint Effect ◽  
Antagonistic Effect ◽  
Acute Test ◽  
Acute And Chronic Toxicity ◽  
Toxicological Studies ◽  
Luminescence Inhibition ◽  
Toxicity Unit

Predicting the crucial effect of single metal pollutants against the aquatic ecosystem has been highly debatable for decades. However, dealing with complex metal mixtures management in toxicological studies creates a challenge, as heavy metals may evoke greater toxicity on interactions with other constituents rather than individually low acting concentrations. Moreover, the toxicity mechanisms are different between short term and long term exposure of the metal toxicant. In this study, acute and chronic toxicity based on luminescence inhibition assay using newly isolated Photobacterium sp.NAA-MIE as the indicator are presented. Photobacterium sp.NAA-MIE was exposed to the mixture at a predetermined ratio of 1:1. TU (Toxicity Unit) and MTI (Mixture Toxic Index) approach presented the mixture toxicity of Hg2+ + Ag+, Hg2+ + Cu2+, Ag+ + Cu2+, Hg2+ + Ag+ + Cu2+, and Cd2+ + Cu2+ showed antagonistic effect over acute and chronic test. Binary mixture of Cu2+ + Zn2+ was observed to show additive effect at acute test and antagonistic effect at chronic test while mixture of Ni2+ + Zn2+ showing antagonistic effect during acute test and synergistic effect during chronic test. Thus, the strain is suitable and their use as bioassay to predict the risk assessment of heavy metal under acute toxicity without abandoning the advantage of chronic toxicity extrapolation.

The study of rotation curve with MOND for ESO138-G014

2013 ◽  
Author(s):  
N. Hashim ◽  
P. Salucci ◽  
Z. Z. Abidin
Keyword(s):  
Rotation Curve

scholarly journals The Dark Matter Halo Density Profile, Spiral Arm Morphology, and Supermassive Black Hole Mass of M33

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Marc S. Seigar
Keyword(s):  
Black Hole ◽  
Dark Matter ◽  
Density Profile ◽  
Pitch Angle ◽  
Rotation Curve ◽  
Dark Matter Halo ◽  
Black Hole Mass ◽  
Supermassive Black Hole ◽  
Virial Mass ◽  
Spiral Arm

We investigate the dark matter halo density profile of M33. We find that the HI rotation curve of M33 is best described by an NFW dark matter halo density profile model, with a halo concentration of and a virial mass of . We go on to use the NFW concentration of M33, along with the values derived for other galaxies (as found in the literature), to show that correlates with both spiral arm pitch angle and supermassive black hole mass.

scholarly journals The stellar velocity field in M 51

1970 ◽  
Vol 38 ◽  
pp. 79-82
Author(s):  
S. M. Simkin
Keyword(s):  
Velocity Field ◽  
Large Deviations ◽  
Rotation Curve ◽  
Radial Velocities ◽  
Absorption Lines ◽  
Image Tube ◽  
Stellar Velocity

Radial velocities have been measured from the absorption lines on two image tube spectra of M 51. These velocities show large deviations from the ‘smoothed’ rotation curve for that object. The measurements seem to indicate that both the stars and the gas move in the same way.

scholarly journals DEEP FABRY-PEROT Hα OBSERVATIONS OF NGC 7793: A VERY EXTENDED Hα DISK AND A TRULY DECLINING ROTATION CURVE

2008 ◽  
Vol 135 (6) ◽  
pp. 2038-2047 ◽  
Author(s):  
I. Dicaire ◽  
C. Carignan ◽  
P. Amram ◽  
M. Marcelin ◽  
J. Hlavacek-Larrondo ◽  
...  
Keyword(s):  
Rotation Curve ◽  
Fabry Perot

scholarly journals The local rotation curve of the Milky Way based on SEGUE and RAVE data

2018 ◽  
Vol 614 ◽  
pp. A63 ◽  
Author(s):  
K. Sysoliatina ◽  
A. Just ◽  
O. Golubov ◽  
Q. A. Parker ◽  
E. K. Grebel ◽  
...  
Keyword(s):  
Rotation Curve ◽  
Milky Way ◽  
Tangential Velocity ◽  
Solar Radius ◽  
Tangential Component ◽  
Peculiar Velocity ◽  
Thick Disc ◽  
Thin Disc ◽  
Peculiar Motion ◽  
Scale Length

Aims. We construct the rotation curve of the Milky Way in the extended solar neighbourhood using a sample of Sloan Extension for Galactic Understanding and Exploration (SEGUE) G-dwarfs. We investigate the rotation curve shape for the presence of any peculiarities just outside the solar radius as has been reported by some authors. Methods. Using the modified Strömberg relation and the most recent data from the RAdial Velocity Experiment (RAVE), we determine the solar peculiar velocity and the radial scale lengths for the three populations of different metallicities representing the Galactic thin disc. Subsequently, with the same binning in metallicity for the SEGUE G-dwarfs, we construct the rotation curve for a range of Galactocentric distances from 7 to 10 kpc. We approach this problem in a framework of classical Jeans analysis and derive the circular velocity by correcting the mean tangential velocity for the asymmetric drift in each distance bin. With SEGUE data we also calculate the radial scale length of the thick disc taking as known the derived peculiar motion of the Sun and the slope of the rotation curve. Results. The tangential component of the solar peculiar velocity is found to be V ⊙ = 4.47 ± 0.8 km s−1 and the corresponding scale lengths from the RAVE data are Rd(0 < [Fe/H] < 0.2) = 2.07 ± 0.2 kpc, Rd(−0.2 < [Fe/H] < 0) = 2.28 ± 0.26 kpc and Rd(−0.5 < [Fe/H] <−0.2) = 3.05 ± 0.43 kpc. In terms of the asymmetric drift, the thin disc SEGUE stars are demonstrated to have dynamics similar to the thin disc RAVE stars, therefore the scale lengths calculated from the SEGUE sample have close values: Rd(0 < [Fe/H] < 0.2) = 1.91 ± 0.23 kpc, Rd(−0.2 < [Fe/H] < 0) = 2.51 ± 0.25 kpc and Rd(−0.5 < [Fe/H] <−0.2) = 3.55 ± 0.42 kpc. The rotation curve constructed through SEGUE G-dwarfs appears to be smooth in the selected radial range 7 kpc < R < 10 kpc. The inferred power law index of the rotation curve is 0.033 ± 0.034, which corresponds to a local slope of dV c∕dR = 0.98 ± 1 km s−1 kpc−1. The radial scale length of the thick disc is 2.05 kpc with no essential dependence on metallicity. Conclusions. The local kinematics of the thin disc rotation as determined in the framework of our new careful analysis does not favour the presence of a massive overdensity ring just outside the solar radius. We also find values for solar peculiar motion, radial scale lengths of thick disc, and three thin disc populations of different metallicities as a side result of this work.

scholarly journals Somatostatin receptors subtypes 2 and 5, dopamine receptor type 2 expression and gsp status as predictors of octreotide LAR® responsiveness in acromegaly

2008 ◽  
Vol 52 (8) ◽  
pp. 1288-1295 ◽  
Author(s):  
Leonardo Vieira Neto ◽  
Giselle Fernandes Taboada ◽  
Mônica Roberto Gadelha
Keyword(s):  
Growth Hormone ◽  
Quantitative Analysis ◽  
Dopamine Receptor ◽  
Molecular Analysis ◽  
Somatostatin Receptor ◽  
Somatostatin Receptors ◽  
Laboratory Data ◽  
Octreotide Lar ◽  
Acute Test ◽  
Igf I

We present two acromegalic patients in which clinical and molecular data are discussed in regard to their ability to predict long term octreotide LAR® therapy response. Case reports: Patient 1: female, 36 years old at diagnosis. Basal GH and IGF-I at diagnosis were 133 ng/mL and 181% above the upper limit of reference values (ULRV), respectively. Growth hormone during acute test with subcutaneous octreotide decreased from 133 to 13 ng/mL. Patient started on primary octreotide LAR® therapy (20mg q28 days) and achieved biochemical parameters of disease control after 6 months. Molecular analysis of tumor fragments: gsp +; quantitative analysis of SSTR (somatostatin receptor) and DR (dopamine receptor) mRNA - SSTR2 23954; SSTR5 2407; DR2 total 17016 copies. Patient 2: male, 38 years old at diagnosis. Basal GH and IGF-I at diagnosis were 120 ng/mL and 114% ULRV, respectively. Patient underwent non-curative trans-sphenoidal surgery. Post-operative GH and IGF-I were 112 ng/mL and 137% ULRV, respectively. Growth hormone during acute test with subcutaneous octreotide decreased from 112 to 7 ng/mL. Octreotide LAR® therapy (20 mg q28 days) was then initiated. After 6 months of treatment, patient did not attain biochemical control of disease and displayed increased tumor volume. Molecular analysis of tumor fragments: gsp not done; quantitative analysis of SSTR and DR mRNA - SSTR2 416; SSTR5 3767; DR2 total 3439 copies. In conclusion, these two cases illustrate how laboratory data can be conflicting as predictors of octreotide LAR® responsiveness and how molecular analysis of tumor fragments can help explain different behaviors in clinically similar patients.

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