scholarly journals Chemical Composition of the Galactic Bulge in Baade's Window

2009 ◽  
Vol 5 (S265) ◽  
pp. 279-284 ◽  
Author(s):  
Andrew McWilliam ◽  
Jon Fulbright ◽  
R. Michael Rich
Keyword(s):  
Chemical Composition ◽  
Massive Stars ◽  
Galactic Bulge ◽  
Rapid Formation ◽  
The Mean ◽  
Red Clump

Abstract1. McWilliam and Zoccali (2009) show the existence of two Red Clump populations towards the Galactic bulge, based on 2MASS data. 2.Measured [Mg/Fe], [Al/Fe], and [La/Eu] ratios in the bulge are consistent with a rapid formation timescale (<1Gyr), which also requires a slightly top-heavy IMF to reproduce the mean bulge metallicity. The [C/O] and [O/Fe] ratios are consistent if their predicted metal-dependent yields from massive stars with winds are considered. The decline in explosive [α/Fe] (Si, Ca, and Ti) can only be understood if their yields also decline with metallicity above [Fe/H]~−1.

scholarly journals Chemical Composition of Planetary Nebulae: A New Determination

1993 ◽  
Vol 155 ◽  
pp. 579-579
Author(s):  
V.V. Golovaty ◽  
Yu. F. Malkov
Keyword(s):  
Chemical Composition ◽  
Massive Stars ◽  
Galactic Disk ◽  
Planetary Nebulae ◽  
Correction Factors ◽  
Galactic Bulge ◽  
Mixing Processes ◽  
Nitrogen Abundance ◽  
The Mean

A new method of the determination of planetary nebulae abundances is proposed. Unobserved ionization stages are taken into account with aid of the correlations between relative abundances of various ions which had been obtained from the grid of the photoionization models of planetary nebulae luminescence calculated by us. Simple approximative expressions for the determination of He/H, C/H, N/H, O/H, Ne/H, Mg/H, Si/H, S/H, and Ar/H are found. The chemical composition of 130 galactic planetary nebulae is revised. The observational data were compiled from 73 papers of many authors published in 1972–1991. Our mean abundances of C, N, O, Ne, S, Ar are 0.1–0.3 dex lower than the mean abundances of these elements found previously by other authors. Such a discrepancy may be due to an overestimation of “empirical” ionization correction factors in previous works. It is shown that the abundance of oxygen in massive stars-precursors may be reduced by 0.2 dex on average due to the ON-cycle, but the abundance of neon remains practically unchanged. A comparative analysis of the abundances in the galactic disk, bulge and halo nebulae is carried out. We found that helium is enhanced in the galactic bulge nebulae relative to the disk ones, but the mean nitrogen abundance and mean ratio N/O are lower in the bulge. Our data suggest that the second dredge-up did not take place in the stars-precursors of the bulge planetaries, and the helium and nitrogen enhancement in these nebulae is due to other mixing processes. The mean abundances of O, Ne, S, Ar in the galactic disk and galactic bulge nebulae are quite similar, and we must conclude that the stars-precursors of the bulge planetaries had been formed during the same burst of star formation as the stars-precursors of the disk nebulae, while the halo nebulae correspond to the previous burst.

scholarly journals The Blanco DECam bulge survey. I. The survey description and early results

2020 ◽  
Vol 499 (2) ◽  
pp. 2340-2356
Author(s):  
R Michael Rich ◽  
Christian I Johnson ◽  
Michael Young ◽  
Iulia T Simion ◽  
William I Clarkson ◽  
...  
Keyword(s):  
Globular Clusters ◽  
Massive Stars ◽  
The Sun ◽  
Horizontal Branch ◽  
Galactic Bulge ◽  
Optical Photometry ◽  
Early Results ◽  
Evolutionary Phase ◽  
Red Clump ◽  
Gaia Dr2

ABSTRACT The Blanco Dark Energy Camera (DECam) Bulge survey is a Vera Rubin Observatory (LSST) pathfinder imaging survey, spanning ∼200 deg2 of the Southern Galactic bulge, −2° &lt; b &lt; −13° and −11° &lt; l &lt; +11°. We have employed the CTIO-4 m telescope and the DECam to image a contiguous ∼200 deg2 region of the relatively less reddened Southern Galactic bulge, in SDSS u  + Pan-STARRSgrizy. Optical photometry with its large colour baseline will be used to investigate the age and metallicity distributions of the major structures of the bulge. Included in the survey footprint are 26 globular clusters imaged in all passbands. Over much of the bulge, we have Gaia DR2 matching astrometry to i ∼ 18, deep enough to reach the faint end of the red clump. This paper provides the background, scientific case, and description of the survey. We present an array of new reddening-corrected colour–magnitude diagrams that span the extent of Southern Galactic bulge. We argue that a population of massive stars in the blue loop evolutionary phase, proposed to lie in the bulge, are instead at ∼2 kpc from the Sun and likely red clump giants in the old disc. A bright red clump near (l, b) = (+ 8°, −4°) may be a feature in the foreground disc, or related to the long bar reported in earlier work. We also report the first map of the blue horizontal branch population spanning the Blanco DECam Bulge Survey field of regard, and our data do not confirm the reality of a number of proposed globular clusters in the bulge.

Influence of the sex and type of tissue on the basic chemical composition and the content of minerals in the sirloin and offal of fattener pigs

2019 ◽  
Vol 99 (2) ◽  
pp. 343-348 ◽  
Author(s):  
Marek Babicz ◽  
Anna Kasprzyk ◽  
Kinga Kropiwiec-Domańska
Keyword(s):  
Chemical Composition ◽  
Mineral Content ◽  
Cadmium Concentration ◽  
Pork Meat ◽  
Threshold Values ◽  
Large White ◽  
Sodium Calcium ◽  
Mineral Components ◽  
Longissimus Lumborum ◽  
The Mean

The aim of the study was to determine the basic chemical composition and mineral content in the sirloin and offal of fattener pigs, taking their sex into consideration. In addition, comparative analysis of the content of chemical and mineral components in the sirloin and offal was performed. The experimental material included 24 crossbred (Polish Landrace × Polish Large White) fatteners, from which samples of sirloin (musculus longissimus lumborum), liver, heart, and kidneys were collected for the analysis. A significant effect of the sex on the fat content in the sirloin and liver and on the level of magnesium (Mg), zinc, and iron (Fe) in the sirloin was demonstrated. Significant differences were found in the basic chemical composition and mineral content between the sirloin and the offal. In comparison with the liver, the sirloin contained lower amounts of protein and fat and higher potassium and Mg contents. In turn, the offal was shown to be a rich source of sodium, calcium, and trace elements (Fe, manganese, and copper). The mean cadmium concentration in the sirloin and offal was significantly lower than the threshold values for these elements, i.e., it accounted for 26% and 6.2% (liver)–19.5% (heart) of the allowable content of this element in pork meat and offal.

scholarly journals Modern quantitative microstructure analysis on the example of aicu5mg1 alloys

2002 ◽  
pp. 109-114
Author(s):  
Biljana Zlaticanin ◽  
Branislav Radonjic ◽  
Branka Jordovic
Keyword(s):  
Grain Size ◽  
Chemical Composition ◽  
Linear Method ◽  
Titanium Content ◽  
Mean Value ◽  
Grain Refining ◽  
Relative Standard ◽  
Method Of Measurement ◽  
The Mean ◽  
Picture Analysis

Using an automatic, QUANTIMET 500 MC, device for quantitative picture analysis and applying linear method of measurement on the example of AlCu5Mg1 alloys, the grain size (min, max and medium values), as well as relative standard measuring errors (RSE), dendrite arm spacing (DAS) and length eutectic (Le) and also distribution by size (histogram) and volume participation of ?-hard solution and eutectic have been determined. We have also studied the influence of grain-refining additives AlTi5B1 for the same chemical composition of the aluminium-capper-magnesium alloy. It has been concluded that with the increase of titanium content, the mean value of grain size decreases. We have also examined hardness and pressure strength.

Efficacy of Hounsfield Unit of CT in Prediction of the Chemical Composition of Urinary Stones

QJM ◽  
2021 ◽  
Vol 114 (Supplement_1) ◽  
Author(s):  
Ahmed Salah Mahmoud Ahmed Shehata ◽  
Mohamed Rafik El-Halaby ◽  
Ahmed Mohamed Saafan
Keyword(s):  
Uric Acid ◽  
Chemical Composition ◽  
Calcium Phosphate ◽  
Calcium Oxalate ◽  
Chemical Structure ◽  
Urinary Calculi ◽  
Hounsfield Unit ◽  
Urinary Stones ◽  
The Mean ◽  
Struvite Stones

Abstract Objectives to make a reliable correlation between the chemical composition of the urinary calculi and its Hounsfield unit on CT scan, upon which we can depend on it for prediction of the type of the urinary calculi. The prediction of the chemical structure of the stone would help us to reach a more efficient therapeutic and prophylactic plan. Methods A retrospective study was performed by interpretation of the preoperative CT scans for patients who were presented by urinary stones. Identification of the chemical structure of the calculi was implemented using Fourier Transform Infrared Spectroscopy (FT-IR spectroscopy). The laboratory report revealed multiple types of stones either of pure or mixed composition. Afterwards, a comparison was done between Hounsfield units of the stones and the chemical structure. Results The chemical structure of the urinary stones revealed four pure types of stones (Uric acid, Calcium Oxalate, Struvite and Cystine) and two types of mixed stones (mixed calcium oxalate+ Uric, and mixed calcium oxalate+ calcium phosphate). Uric acid stone had a mean Hounsfield Unit (HU) density of428 ± 81, which was quite less than the other stones, followed by struvite stones with density ranging about 714 ± 38. Mixed calcium oxalate stones could be differentiated from other types of stones like uric acid, pure calcium oxalate and struvite stones by the Hounsfield unit of Computed Tomography (the mean Hounsfield Unit was 886 ± 139 and 1427 ± 152 for mixed calcium oxalate + uric stone and mixed calcium oxalate + calcium phosphate stones respectively). Moreover, pure calcium oxalate stones were easily differentiated from all other stones using the mean Hounsfield density as it was 1158 ± 83. It was challenging only when it was compared to cystine stones, as they were quiet similar to HU value (997 ± 14). The variation of Hounsfield values among the previously mentioned stones, was statistically significant (p &lt; 0.001). Conclusion The study proved that the Hounsfield Unit of CT scanning is a convenient measure to predict the chemical structure of urinary calculi.

Chemical Composition and Repellency Effect of Ferulago Angulate Plant Against Malaria Vector, Anopheles Stephensi

2020 ◽  
Author(s):  
Masoumeh Pirmohammadi ◽  
Mansoureh Shayeghi ◽  
Mohammad Reza Abai ◽  
Hassan Vatandoost ◽  
Sara Rahimi ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Chemical Composition ◽  
Malaria Vector ◽  
Anopheles Stephensi ◽  
Control Measures ◽  
Gas Chromatography Mass Spectrometry ◽  
Anopheles Mosquitoes ◽  
Protection Time ◽  
The Mean

Abstract BackgroundMalaria is a health problem globally. There are several vector control measures. Using repellent to protect human from biting of vectors is one of the best ways. The aim of this study is to evaluate the efficacy of plant against biting of malaria vector, An.stephensi under laboratory conditions.MethodsChemical constituents of Ferulago angulate plant were determined by using gas chromatography-mass spectrometry. Efficacy and the protection time of plant were evaluated on Anopheles stephensi . ResultsA total of 40 compounds were identified in plant. Flourensiadiol (17.4%) dehydro-sabina keton (13.3%), β-maaliene (8.8%) was the highest in the plant. The mean assessed protection time and efficacy for plant was 60 and 100 minutes respectively. ED50 and ED90 values for this plant were 18.12 and 93.19 µl /cm2 respectively.ConclusionResults showed that plant has an acceptable protection time, therefore, this plant could be considered as a good herbal repellent against anopheles mosquitoes.

scholarly journals Non-parametric density reconstruction of the Galactic bulge area using red clump stars in the VVV survey

2020 ◽  
Vol 499 (2) ◽  
pp. 1937-1947
Author(s):  
Dylan Paterson ◽  
Brendan Coleman ◽  
Chris Gordon
Keyword(s):  
Parametric Method ◽  
Major Axis ◽  
Galactic Bulge ◽  
Buckling Instability ◽  
Giant Stars ◽  
Red Clump ◽  
Red Giant ◽  
High Resolution Reconstruction ◽  
Spiral Arm ◽  
Non Parametric

ABSTRACT Studies of the red clump giant population in the inner Milky Way suggest the Galactic bulge/bar has a boxy/peanut/X-shaped structure as predicted by its formation via a disc buckling instability. We used a non-parametric method of estimating the Galactic bulge morphology that is based on maximum entropy regularization. This enabled us to extract the 3D distribution of the red giant stars in the bulge from deep photometric catalogues of the VISTA Variables in the Via Lactea survey. Our high-resolution reconstruction confirms the well-known boxy/peanut/X-shaped structure of the bulge. We also find spiral arm structures that extend to around 3 kpc in front of and behind the bulge and are on different sides of the bulge major axis. We show that the detection of these structures is robust to the uncertainties in the luminosity function.

scholarly journals Chemical Abundances in Galactic Bulge Pn

1993 ◽  
Vol 155 ◽  
pp. 581-581 ◽  
Author(s):  
N.A. Walton ◽  
M.J. Barlow ◽  
R.E.S. Clegg
Keyword(s):  
Galactic Disk ◽  
Planetary Nebulae ◽  
Solar Neighbourhood ◽  
Galactic Bulge ◽  
Low Resolution ◽  
Chemical Abundances ◽  
The Mean ◽  
Optical Spectrophotometry ◽  
High Metallicity

We present abundance determinations, in particular of carbon, and C/O ratios, for 11 Galactic bulge planetary nebulae (PN) based on our low resolution UV data from IUE observations and optical spectrophotometry from the Anglo-Australian Telescope. We compare the observed abundances with those predicted by dredge-up theory for the high metallicity Galactic bulge. The sample abundances are also contrasted with the abundances found for PN in the Galactic disk. The mean C/O ratio for the bulge PN is significantly lower than that found for Galactic disk PN. Further, we present an abundance analysis of the very metal-poor bulge PN M2-29. From an analysis of the differential extinction found from the observed ratios of the He ii 1640,4686Å lines, we find that the ultraviolet reddening law towards the bulge is steeper than in the solar neighbourhood.

scholarly journals The last breath of the Sagittarius dSph

2020 ◽  
Vol 497 (4) ◽  
pp. 4162-4182 ◽  
Author(s):  
Eugene Vasiliev ◽  
Vasily Belokurov
Keyword(s):  
Milky Way ◽  
Dwarf Galaxy ◽  
3D Structure ◽  
Major Axis ◽  
Final State ◽  
Tidal Forces ◽  
The Galaxy ◽  
The Mean ◽  
Red Clump ◽  
Astrometric Data

ABSTRACT We use the astrometric and photometric data from Gaia Data Release 2 and line-of-sight velocities from various other surveys to study the 3D structure and kinematics of the Sagittarius dwarf galaxy. The combination of photometric and astrometric data makes it possible to obtain a very clean separation of Sgr member stars from the Milky Way foreground; our final catalogue contains 2.6 × 105 candidate members with magnitudes G &lt; 18, more than half of them being red clump stars. We construct and analyse maps of the mean proper motion and its dispersion over the region ∼30 × 12 deg, which show a number of interesting features. The intrinsic 3D density distribution (orientation, thickness) is strongly constrained by kinematics; we find that the remnant is a prolate structure with the major axis pointing at ∼45° from the orbital velocity and extending up to ∼5 kpc, where it transitions into the stream. We perform a large suite of N-body simulations of a disrupting Sgr galaxy as it orbits the Milky Way over the past 2.5 Gyr, which are tailored to reproduce the observed properties of the remnant (not the stream). The richness of available constraints means that only a narrow range of parameters produce a final state consistent with observations. The total mass of the remnant is $\sim \!4\times 10^8\, \mathrm{M}_\odot$, of which roughly a quarter resides in stars. The galaxy is significantly out of equilibrium, and even its central density is below the limit required to withstand tidal forces. We conclude that the Sgr galaxy will likely be disrupted over the next Gyr.

scholarly journals The Trouble with Venus

1971 ◽  
Vol 40 ◽  
pp. 116-127
Author(s):  
Carl Sagan
Keyword(s):  
Dielectric Constant ◽  
Chemical Composition ◽  
Surface Temperature ◽  
Rotation Axis ◽  
Order Unity ◽  
Naked Eye ◽  
Atmospheric Structure ◽  
Data Points ◽  
The Mean ◽  
Temperature And Pressure

Venus is the closest planet. Its surface has never been seen at optical frequencies; nevertheless we now know with at least fair reliability, and in some cases with remarkable accuracy, its surface temperature and pressure, its atmospheric structure, its period of rotation, the obliquity of its rotation axis, the mean surface dielectric constant, its ionospheric structure, and even a little about its surface topography. And yet the clouds of Venus, visible to the naked eye and known to be clouds since the time of Lomonsov, continue to elude our efforts to understand them comprehensively. Not only do we disagree on the chemical composition of the clouds, but it is not even settled whether they are condensation clouds or non-condensable aerosols. And yet there is a very wide variety of relevant data on the clouds. Indeed, the ratio of potentially diagnostic data points to mutually exclusive hypotheses is of the order unity.

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