... Title : DETERMINATION OF THE ISOTOPIC RATIOS OF ... Descriptors : *CARBON, *HYDROGEN, ABUNDANCE, CHEMICAL ANALYSIS, ISOTOPES. ...

... Title : ABUNDANCES OF ELEMENTS IN STARS AND NEBULAE (DETERMINATION OF RATIO OF GAS PRESSURE TOELECTRON PRESSURE ...

Oct 1, 2010 ... This experiment was designed to determine the isotopic abundance in the primary cosmic rays for hydrogren through nickel. ...

For red giants, a smooth increase in the nitrogen to carbon abundance ratio for increasing B-V as is expected for the first dredge up phase when the outer convection zone deepens, is found. An average increase in the nitrogen to silicon ratio for B-V = 0....

Following Thomson's discovery of stable isotopes in non-radioactive chemical elements, the derivation of atomic weight values from mass spectrometric measurements of isotopic abundance ratios moved very slowly. Forty years later, only 3 1/2 % of the recom...

Measurements of actinide and light REE (LREE) abundances and of phosphate abundances in equilibrated ordinary chondrites were obtained and were used to define the Pu abundance in the solar system and to determine the degree of variation of actinide and LREE abundances. The results were also ...

A nonphotometric method for the determination abundances in nearby galaxies is presented. The method involves a theoretical calibration of the observed strong correlation between the ratio of cool carbon states to M giants (C/M ratio) with metal abundance, assuming that carbon stars are ...

BS>The ratio of the sulfur isotope ratio, /sup 34/S/(/sup 32/S + /sup 32/ S), in a sample of sulfur hexafluoride to that in an isotopically different sample (relative ratio) is determined to plus or minus 0.00003 (standard deviation) at relative ratios of 1.003-1.007 and near-natural ...

Mar 1, 2011 ... for the trace determination of silicon at a mass-to-charge (m/z) ratio of 28, the most abundant natural isotope of silicon. ...

The manganese stars show abundance anomalies that are in conflict with the predictions of nuclear astrophysics. The paper stresses the deviations from the odd-even effect that occur for phosphorus, gallium, and yttrium. The abundance anomalies (e.g., the Mn/Fe ratio) in the iron peak are less serious; within the uncertainties of the ...

By means of a gamma ray sum spectrometer currently under development, many neutron capture cross sections will be determined with high accuracy, thereby facilitating the inferrence of the abundance ratios of neighboring elements with the same accuracy. Attention is presently given to this and other prospects emerging in the study of ...

A compilation of galactic elemental abundances with realistic error estimates is presented and compared with cosmic ray abundances in order to determine the composition of the galactic cosmic ray source. Galactic abundances were determined from the compositions of meteorites, the solar ...

An Ar/Fe abundance ratio of 0.031 + or - 35 percent and an upper limit of 0.4 to the Ne/Mg abundance ratio are determined for solar coronal active regions using solar spectra. Forbidden lines occur at 1324.45 A for Mg V, 1349.38 A for Fe XII, 1375.98 A for Ca XV, and 1392.12 A for Ar XI. The ...

The nickel abundances of most of the major occurrences of tektites, as well as several meteorite impact glasses and obsidians, were determined using neutron activation analysis. Iron abundances were determined in the same specimens; and Ni/Fe abundance ratios were ...

The abundance ratio of 13C enriched carbon films was determined by means of the Mattauch-Herzog type mass spectrograph. Electrodes of type C(Au)/(Pt) for the vacuum spark ion source were mounted. Platinum isotope mass spectra on the same photographic plat...

The Rb/sup 85//Rb/sup 87/ abundance ratio for a reference sample of rubidium sulfate was determined as 2.5995 450 deg C in a 0.0015 (95 per cent confidence interval) on a mass spectrometer with a 12-inch radius of curvature and a triple-filament mode of ionization. The abundance ratio ...

The aim of the proposal was to determine the nitrogen to carbon abundance ratios from transition layer lines in stars with different Teff and luminosities. The equations which give the surface emission line fluxes and the measured ratio of the NV to CIV emission line fluxes are presented and explained. The ...

Chemical abundances of the elements He, N, C, and Cl are presented for disk planetary nebulae, comprising Peimbert types I, II, and III. Average abundances for these classes are determined and compared with the remaining abundances available. The presence of abundance gradients relative to ...

If deuterium is made primarily in stars, then according to current models of galactic evolution it should have a higher abundance in the metal-rich parts of the Galaxy. If it is produced only in the initial big bang, then astration causes a decrease in D abundance with increasing metal abundance z. Since the sign of the ...

Cerium isotope ratios were determined for Juvinas, Pasamonte and ALH-78132 eucrites and the Jilin (H4) chondrite. Neodymium isotope ratios and abundances of lanthanum, cerium, neodymium and samarium were also determined for these meteorites. The La-Ce isotopic system, coupled with the Sm-Nd ...

A short review on abundance determinations of A and F dwarfs in the Hyades is presented. The spectroscopy was carried out with AURELIE, a monorder spectrograph at the Observatoire de Haute Provence (France) at a resolving power close to 40000 with Signal-to-Noise ratios varying from 100 to 300. Abundances of 11 ...

It is demonstrated that the abundances of the intermediate and light lanthanides in the Am star 32 Aqr are comparable in magnitude to those in the cool magnetic Ap stars Gamma Equ and 10 Aql. The similarity in the lanthanide abundances for these stars was anticipated from wavelength coincidence studies, which also suggested that the Nd/Sm ...

Resonance ionization mass spectrometry (RIMS) has become a sensitive and highly selective technique for the determination of extremely low elemental or isotopic abundances, involving isotope ratio measurements with dynamical ranges of 109 and beyond. The experimental detection limits are as low as 106 atoms per sample, and isotopic ...

We demonstrate that when there are gas density variations within a nebula, various line ratios used to determine electron density (Ne) can give different results. When there are non-constant density conditions, it is shown that by using one (average) Ne, significant, systematic biases may occur in the derived chemical abundance ...

The utility of the emission-line ratio (3727 + 4959 + 5007 A)/H-beta as an estimate of the total oxygen abundance in H II regions of low abundance (less than 10 percent of the solar value) is discussed. Using both observational data where the 4363A line is measured and model H II regions it is concluded that, for low ...

example, forming the ratio of the abundances of methanol and methylamine would result in .... anol and methylamine should give the abundance ratio ...

>A 13-kg sample of highly purified Li/sub 2/CO/sub 3/ prepared from virgin ores was assayed to have an absolute /sup 6/Li//sup 7/Li abundance ratio of 0.0832 plus or minus 0.0002. This value was determined by a mass spectrometric comparison with a primary standard blended from specially prepared, highly enriched, ...

One drop of 200 mg/ml LiI solution is deposited in the ionization case. Under conditions such that the max peaks of Li/sup 7/ and Li/sup 6/ can be obtained, the peaks due to these isotopes are recorded repeatedly. More than 20 measured values of the abundance ratio in the region around the point on which the ionization current reaches a max are ...

Chemical abundances of 25 alpha-, iron peak-, and neutron-capture elements in the remote (R=90kpc) outer halo globular cluster have been determined for 4 red giants observed with the Magellan/MIKE spectrograph and from integrated spectra of 19 stars obtained with the Keck/HIRES instrument. The resulting abundance ...

The primordial abundance of deuterium produced during Big Bang Nucleosynthesis (BBN) depends sensitively on the universal ratio of baryons to photons, an important cosmological parameter probed independently by the Cosmic Microwave Background (CMB) radiation. Observations of deuterium in high-redshift, low-metallicity QSO Absorption Line Systems (QSOALS) ...

The primordial abundance of deuterium produced during Big Bang Nucleosynthesis (BBN) depends sensitively on the universal ratio of baryons to photons, an important cosmological parameter probed independently by the Cosmic Microwave Background (CMB) radiation. Observations of deuterium in high-redshift, low-metallicity QSO Absorption Line Systems (QSOALS) ...

Gravimetric synthetic mixtures of seven enriched, purified cadmium isotope materials were used to determine the correction factors for mass fractionation (MC-TIMS) and mass discrimination (MC-ICP-MS). The isotope abundance ratios determined for various natural cadmium materials represents the isotope composition ...

We describe the current status of a programme we started a few years ago to observe a large number of A/F and Am/Fm stars in open clusters of various ages. Spectra were obtained with the AURELIE and ELODIE spectrographs at a resolving power of about 40000 and S/N ratios from 100 up to 500. Abundances of 11 chemical elements have been derived by using ...

Using the WMAP determination of the baryon density, the standard model of big bang nucleosynthesis yields relatively precise predictions of the primordial light-element abundances. Currently there are two significantly different observational determinations of the primordial helium abundance, and if only ...

Oscillator strengths have been determined from measurements of radiative lifetimes and branching ratios for 154 lines of Y I and 66 lines of Y II. These data are used, together with equivalent widths measured on the Jungfraujoch solar atlas, to perform a new determination of the solar abundance of yttrium: A/sub Y/ ...

We present measurements of the C18O/C17O abundance ratio based on observations of J=1-->0 lines of these isotopomers toward star-forming cores in the Taurus molecular cloud. Our data set includes measurements along 648 lines of sight through these clouds, covering both low and high column density regions. We compare the integrated intensity ...

... abundances is given only for the most abundant isotope, so the ... Analysis of SW elemental abundance data from the NASA Genesis mission is not ...

The [Zr/Ti] ratio for a large sample of Galactic S stars has been determined using high-quality, high-resolution spectra. The pattern of Zr enhancements in intrinsic and extrinsic S stars is found to differ, and the [Zr/Ti] ratio in the extrinsic S stars clearly links them to the strong barium stars. In addition, the pattern of [Zr/Ti] ...

The bulk chemical composition of Orgueil and 25 other carbonaceous chondrites was determined by x-ray fluorescence analysis. The sample sizes of the analyzed meteorites were in all cases 120 mg. The abundances of P and Ti in Orgueil and Ivuna were precisely determined by the standard addition method. The new P CI ...

A nondestructive method for determining plutonium isotopic abundance ratios, based on the detection and measurement of the gamma rays emitted, is now being accepted as routine for solution samples. The analysis of solid samples is of more general interest...

Scientific goals include a better determination of the basic physical characteristics of cometary nuclei, a more complete understanding of the complex processes in the comae, a survey of abundances and gas/dust ratios in a large number of comets, and meas...

The relative multiplicity abundance K/sup +//..pi../sup +/ and K/sup +//p/sup +/ arising in quark-gluon plasma formed in high energy nuclear collisions is determined. It is shown how these ratios assist in discriminating between various reaction channels.

The isotope dilution mass spectrometry with (sup 233)U as a single internal standard has been developed. It can be used to determine the abundant ratio precisely in the uranium sample. It is an absolute measurement method based on gravimetry. The (sup 233...

Work on completing our analysis of the Voyager UVS solar occultation data acquired during Neptune encounter is essentially complete, as testified by the attached poster materials. The photochemical modeling addresses the recent revision in branching ratio...

The share of free neutral atoms, N(sub 0), for all elements in Protoplanet nebula has been determined with the account of their abundance and physico-chemical properties. The linear dependence for the ratio of nonvolatile and volatile elements in chondrit...

In this study we present abundances of 12C, 13C, N, O and up to 26 other chemical elements in two first-ascent giants and two core-helium-burning 'clump' stars of the open cluster NGC 2506. Abundances of carbon were derived using the C2 Swan (0,1) band head at 5635.5 �. The wavelength interval 7940-8130 �, with strong CN features, was analysed in order ...

In this study we present abundances of 12C, 13C, N, O and up to 26 other chemical elements in two first-ascent giants and two core-helium-burning 'clump' stars of the open cluster NGC 2506. Abundances of carbon were derived using the C2 Swan (0,1) band head at 5635.5 �. The wavelength interval 7940-8130 �, with strong CN features, was analysed in order ...

Carbon, nitrogen, and oxygen abundances have been determined for 11 G and K giants. High-resolution photoelectric scans of C/sub 2/, CH, CN, (O I), and (C I) lines have been combined with recent model atmospheres. Relative to the solar atmosphere, the C abundances are depressed, the N abundances enhanced, and the O ...

Heavy element abundances in extremely metal-poor stars provide strong constraints on the processes of forming these elements in the first stars. We attempt to determine precise abundances of strontium in a homogeneous sample of extremely metal-poor stars. The abundances of strontium in 54 very or extremely ...

Context. Heavy element abundances in extremely metal-poor stars provide strong constraints on the processes of forming these elements in the first stars. Aims: We attempt to determine precise abundances of strontium in a homogeneous sample of extremely metal-poor stars. Methods: The abundance of strontium in 54 ...

Results are reported for Copernicus observations of the 1362.46-A resonance line of B II in 16 normal B and A stars. An average for the stars in which a boron abundance has been determined yields a B/H abundance ratio of 2 x 10 to the -10th; this value is taken to be the cosmic abundance of ...

Appropriate corrections for 2H and 18O natural abundance are necessary in energy expenditure measurements with the doubly labeled water (DLW) method. The contribution of natural abundance variations to errors in the method is generally ignored if an appropriate dose level is given. Calculation of the appropriate dose level assumes that 2H and 18O natural ...

A relationship between the calculated emission functions for Ne X and Mg XI is discussed and used for determining the relative solar coronal abundance of neon and magnesium. The relative abundance is calculated directly from the relative intensity of the resonance lines of Ne X(12.134 A) and Mg XI (9.169 A) without the need for the ...

A technique is proposed for specifically determining the relative solar coronal abundance of neon and magnesium. The relative abundance is calculated directly from the relative intensity of the resonance lines of Ne X (12.134A) and Mg XI (9.169A) without the need for the development of a detailed model of the thermal structure of the ...

An examination of the isotopic abundance ratio in natural silver by means of the mass spectrometer resulted in a value of 1.0733 plus or minus 0.0043 for the absolute isotopic abundance ratio Ag/sup 107//Ag/sup 109/. Specimens of commercial silver of diverse ages possess abundance ...

We have determined the C-12/C-13 ratio in 8 M giants and combined our data with previous measurements to establish that in early M giants C-12/C-13 = 11.8 +/- 3.8, where 3.8 is the dispersion, not the standard error of the mean. This low ratio, comparable to the ratio in the coolest red giants and clump stars in ...

Acceleration of energetic ions in solar flares produces narrow and broad nuclear ?-ray de-excitation lines, by nuclear interactions with the ambient solar atmosphere. Observations of several solar flare ?-ray spectra have been made since 1972 by satellite-borne ?-ray spectrometers on OSO 7, HEAO 3, SMM, HINOTORI, GRANAT, YOHKOH and CGRO. The line intensities depend directly on the ambient and ...

abundance ratios were based on simple models. The nebulae were assumed to be uniform density spheres in LTE broad classes: (1) ``complex'' sources which require non�LTE multiple�component density models; and (2) ``simple'' sources which are adequately described using LTE uniform density sphere models. Because

The main aim of this research program is to determine the ionization equilibrium and abundances in quasar outflows. Especially in the broad absorption line QSO PG 0946+301. We find that the outflow's metalicity is consistent with being solar, while the abundance ratio of phosphorus to other metals is at least ten ...

mussels collected from Lake St. Clair, and (2) seasonally determine lipid content and C:N ratios of soft tissue from zebra mussels collected from Lake St. Clair. During FY 90, zebra mussels were collected from two sites in Lake St. Clair (one site with high abundance and one with low abundance) once a month

with the expansion rate of the Universe during the big bang nucleosynthesis(BBN). This has been used to put limits depends on the baryon to photon ratio j. We can determine j by either measuring deuterium abundance that there are three neutrino species, and adopt j � 4:5 as inferred from the deuterium abundance, ...

The abundances of up to 20 elements are measured in cool supergiants in Magellanic young populous clusters (NGC 330 in the SMC, NGC 1818 and NGC 2100 in the LMC), and compared to those, recently observed in samples of field supergiants in each Cloud (Hill et al. 1997). The analysis of the field supergiants showed no evidence of any abundance dispersion ...

The interior structure of the Sun can be studied with great accuracy using observations of its oscillations, similar to seismology of the Earth. Precise agreement between helioseismological measurements and predictions of theoretical solar models has been a triumph of modern astrophysics. A recent downward revision by 25-35 per cent of the solar abundances of light elements ...

The relative elemental abundances of iron, oxygen, magnesium, and neon in the solar corona are investigated with simultaneous broadband and spectral-line soft X-ray data. Coordinated observations of a solar active region were made by the American Science and Engineering High Resolution Soft X-Ray Imaging Sounding Rocket Payload, and by the X-ray Polychromator Flat Crystal ...

Measurements of the O-16 and O-18 distribution functions in the solar wind at low to average solar wind speeds from the MASS instrument on the Wind spacecraft are reported. The O-16/O-18 density ratio is 450 +/- 130, a value consistent with terrestrial, solar photospheric, solar energetic particle, and galactic cosmic ray O-16/O-18 isotopic ratios. This ...

The abundances of the actinide elements in the cosmic rays can provide critical constraints on the major sites of their acceleration. Using recent calculations of the r-process yields in core-collapse supernovae (SNe), we have determined the actinide abundances averaged over various assumed time intervals for their supernovae ...

The abundances of zirconium and hafnium have been determined in nine stony meteorites by a new, precise neutronactivation technique. The Zr/W abundance ratios for the chondrites vary in a rather narrow rarge, consistent with previously published observations. Replicate analyses of new, carefully selected ...

Solar energetic particles (SEPs) provide a measurement of coronal element abundances that is highly independent of the ionization states and temperature of the ions in the source plasma. The most complete measurements come from large 'gradual' events where ambient coronal plasma is swept up by the expanding shock wave from a coronal mass ejection. Particles from 'impulsive' ...

NH2 emission band strengths were measured in four comets and the NH2 column densities were determined in order to measure the ammonia content of the comets. The mean ammonia/water abundance ratio derived for the four comets is found to be 0.13 + or - 0.06 percent, with no significant variation among the comets. The uniformity of this ...

Usiang high-resolution spectra and line-blanketed model atmospheres, we have carried out abundance analyses of he strong-lined K dwarf 14 Her and the normal K dwarf 70 Oph A. We confirm previous studies of high-resolution spectra of 14 Her which have shown it to be metalrich; we find an overall enhancement of a factor of 2.5 compared to both the Sun and 70 Oph A. Relative ...

Two ionic lines observed in the sun at 4068.334 and 5103.125 A and attributed to Sm have been analyzed assuming LTE. Oscillator strengths, obtained from lifetimes and branching-ratio measurements, are used for the abundance determination. Using the spectral synthesis method, the Sm abundance derived from these two ...

Problems related to the oscillator strengths in Sr II, Y II, and Zr II are discussed, and new accurate transition probabilities are reported that are derived from measurements of lifetimes and branching ratios of Y II and Zr II lines present in the spectra of chemically peculiar stars of the upper main sequence. These oscillator strengths are compared with other sets of ...

We have determined fluorine abundances from the [F II] ?4789 and [F IV] ?4060 nebular emission lines for a sample of planetary nebulae (PNe). Our results show that fluorine is generally overabundant in PNe, thus providing new evidence for the synthesis of fluorine in asymptotic giant branch (AGB) stars. [F/O] is found to be positively correlated with the ...

A fine analysis of nine southern supergiants of spectral types F through K, including the bright Cepheid variable l Car, is presented. The average metal-to-hydrogen ratio is found to be twice the solar value. No essential differences are found between the nonvariable stars and the Cepheid variable.In an initial attempt to determine the spatial distribution ...

The radiative lifetimes of 39 levels in V I have been measured by the method of laser-induced fluorescence from sputtered metal vapor. Emission branching ratios have been measured for these levels to determine absolute transition probabilities for 208 lines in the wavelength range 3180 � to 16,400 �. These transition probabilities are used together ...

Methods for the measurement of the natural isotopic abundance of Li are discussed. The construction of a mass spectrometer for the analysis of solids is described. The influence of mass dependence of the evaporation, focusing of the ions, and secondary effects in the collector on accuracy and reproducibility are discussed in detail. An equation for the vapor ...

Vanadium-to-hydrogen ratios have been determined for Omicron Peg, HR 6127, HR 465 (rare-earth minimum), and HR 8216. With respect to the solar system, vanadium is overabundant in the first two stars, possibly normal in the third, and underabundant in the fourth. The range in the V/H ratio in these four stars is between one and two ...

Aluminum and other metal abundances were determined in 21 red giants in the globular clusters NGC 6752 and M80 as part of a larger study to determine whether the aluminum distribution on the red giant branch is related to the second parameter effect that causes clusters of similar metallicity to display different horizontal branch ...

The purpose of this work is to resume investigation of Galactic thin disk dating using nucleocosmochronology with Th/Eu stellar abundance ratios, a theme absent from the literature since 1990. A stellar sample of 20 disk dwarfs/subgiants of F5 to G8 spectral types with -0.8?[Fe/H]?+0.3 was selected. In stars with such spectral types and luminosity classes, ...

Progress during the past 35 years in research to determine the isotopic composition of boron is reviewed. Chemically determined atomic weights have a relatively large uncertainty, while results obtained from mass spectra of boron trifluoride have been unreliable because of experimental difficulties. On the other hand, ...

Using numerical analysis it is demonstrated that when there are changes in gas density within a nebulae various empirical methods for determining the electron density can give different results. Eleven different species are considered which have line pair ratios that are well-known electron density (Ne) diagnostic tools. In the presence of varying density, ...

To compare the abundance of an element relative to hydrogen, take the ratio of the abundances: 5. How much more hydrogen is there in the solar system than ...

Moreover, there are abundance variation within structures: streamers' abundances are ... FIP element ratio that is anticorrelated with the solar wind speed. ...

Noble gas abundance and isotope ratios in the atmosphere of Jupiter from the Galileo Probe Mass Spectrometer. P. R. Mahaffyf H. B. Niemann,1 A. Alpert} ...

... Title : A Comparison of Elemental Abundance Ratios in SEP Events in Fast and Slow Solar Wind Regions. Descriptive Note : Journal article reprint. ...

For some sets of surfaces, the spatial ratios of cone-photoreceptor excitations produced by light reflected from pairs of surfaces are almost invariant under illuminant changes. These sets include large populations of spectral reflectances, some of which represent individual natural surfaces but not their relative abundances in nature. The aim of this ...

Review was made on the determination of isotopic abundance ratio by the mass spectroscopic method, relation between the abundance ratio and atomic weight, problems in the relative measurement of the ratio, standard materials for the determination ...

The concentrations of B in seven carbonaceous chondritic meteorites have been determined by the use of two different analytical techniques. The data correspond to a B/H ratio of about 1 billionth as compared with the value of 1 hundred millionth previously proposed by Cameron, Colgate, and Grossman (1973). However, the meteoritic ...

The use of multidimensional capillary HPLC combined with tandem mass spectrometry has allowed high qualitative and quantitative proteome coverage of prokaryotic organisms. The determination of protein abundance change between two or more conditions has matured to the point that false discovery rates can be very low and for smaller proteomes coverage is ...

Aims: LTE abundances of light elements in extremely metal-poor (EMP) stars have been previously derived from high quality spectra. New derivations, free from the NLTE effects, will better constrain the models of the Galactic chemical evolution and the yields of the very first supernovae. Methods: The NLTE profiles of the magnesium and potassium lines have been computed in a ...

Context. The abundances of elements in the atmosphere of an individual star provide a very broad range of extremely important information about the formation and evolution history of that star. Specifically, during the main sequence phase, the abundance pattern observed can provide valuable constraints on a range of hydrodynamical processes occurring ...

We present high-quality observations of Neii optical recombination lines (ORLs) for the bright Saturn Nebula NGC 7009. The measured line fluxes are used to determine Ne2+/H+ abundance ratios. The results derived from individual multiplets of the 3s-3p and 3p-3d configurations agree reasonably well, although values derived from the ...

Context. Gamma-ray bursts (GRBs) were the most energetic events after the Big Bang and they have been observed up to very high redshift. Measurements of the chemical abundances are now available for the galaxies hosting such events, which are assumed to originate from the explosion of very powerful supernovae (Type Ib/c), and provide the opportunity to study the nature of ...

The Hipparcos orbiting observatory has revealed a large number of helium-core-burning �clump� stars in the Galactic field. These low-mass stars exhibit signatures of extra mixing processes that require modelling beyond the first dredge-up of standard models. The 12C/13C ratio is the most robust diagnostic of deep mixing because it is insensitive to the adopted stellar ...

Oscillator strengths for 154 Y I lines and 66 Y II lines with wavelengths between 2948 and 7055 A are determined by combining laboratory measurements of radiative lifetimes and branching ratios. Lifetimes are presented for 34 levels of Y I and 14 levels of Y II; branching ratios are given for all levels below 9000 A with parity change ...

The composition of the jovian atmosphere from 0.5 to 21 bars along the descent trajectory was determined by a quadrupole mass spectrometer on the Galileo probe. The mixing ratio of He (helium) to H2 (hydrogen), 0.156, is close to the solar ratio. The abundances of methane, water, argon, neon, and hydrogen sulfide ...

Context: We present deep archival VLT/FORS1+UVES spectroscopic observations of the system of two blue compact dwarf (BCD) galaxies SBS 0335-052E and SBS 0335-052W. Aims: Our aim is to derive element abundances in different H ii regions of this unique system of galaxies and to study spatial abundance variations. Methods: The electron temperature Te (O ...

Isotope variability due to natural processes provides important information for studying a variety of complex natural phenomena from the origins of a particular sample to the traces of biochemical reaction mechanisms. These measurements require high-precision determination of isotope ratios of a particular element involved. Isotope ...

Calculations have been performed to determine the rate coefficients of several reactions involved in both the formation and depletion of interstellar HCO/sup +/ andd HOC/sup +/. The abundance of HOC/sup +/ deduced from these calculations is consistent with the tentative identification of HOC/sup +/ in Sgr B2 by Woods et al. The large HCO/sup +//HOC/sup +/ ...

The biological marker oleanane has been suggested as an indicator of angiosperm (flowering plant) input into source rocks and their derived oils. Parallels should therefore be evident between the angiosperm fossil record and oleanane occurrence and abundance. A global selection of more than 50 core samples from marine rocks of different ages and from different locations was ...

Atmospheric parameters (Teff , log g, [Fe/H], Vt), Li, and volatile (O, Na, Al, Zn) and refractory (Si, Ti, V, Cr, Co and Ni) element abundances in 133 stars belonging to the low part of MS have been determined. Among them about 30 stars are the variable stars of BY Dra type, for which the determination of the chemical composition was ...

The difference in the stable sulfur isotope ratios of sulfate and sulfide in marsh pore water was used to verify the uptake of hydrogen sulfide by the salt marsh cordgrass Spartina alterniflora in a North Carolina salt marsh. Most of the plant sulfur derived from pore-water sulfide was recovered as sulfate, an indication that the sulfide had been oxidized within the plant. The ...

The enantiomeric ratios of alpha-HCH were determined by chiral gas chromatography in blubber of marine mammals from regions of the northern hemisphere (North Sea, Baltic Sea, Arctic and Iceland). Cetaceans (harbour porpoises and white-beaked dolphins) showed a preferential accumulation of (+)-alpha-HCH. In blubber of harbour seals, grey seals and harp ...

The abundances of up to 20 elements are measured in cool supergiants in Magellanic young populous clusters (NGC330 in the SMC, NGC1818 and NGC2100 in the LMC), and compared to those, recently observed in samples of field supergiants in each Cloud. The analysis of the field supergiants showed no evidence of any abundance dispersion among the stars, ...

Detailed abundances are measured in cool (K type) supergiants in LMC young populous clusters (NGC 2004, NGC 2100 and NGC 1818), and compared to those, recently observed in samples of field supergiants in both Magellanic Clouds. This completes the work already done onthe SMC cluster NGC 330 (Hill et al., 1997b).The analysis of the field supergiants showed no evidence of any ...

The aim of this paper is to provide fundamental parameters and abundances with a high accuracy for a large sample of cool main sequence stars. This study is part of wider project, in which the metallicity distribution of the local thin disc is investigated from a complete sample of G and K dwarfs within 25pc. The stars were observed at high resolution and a high ...

We present measurements of the relative abundances of cosmic-ray nuclei in the energy range of 500-3980 GeV/nucleon from the second flight of the Cosmic Ray Energetics And Mass (CREAM) balloon-borne experiment, extending the energy range beyond the reach of previ-ous measurements. Particle energy is determined using a sampling tungsten/scintillating-fiber ...

The results are given of a quantitative analysis of the chemical composition of the filaments in the Crab nebula based on the numerous published spectra of individual filaments. The method employed is based on a comparison of the relative abundances obtained from observations for two adjacent ionization stages of one element - for example, O(2+)/He(+) and O(+)/He(+) - with the ...

The results are given of a quantitative analysis of the chemical composition of the filaments in the Crab nebula based on the numerous published spectra of individual filaments. The method employed is based on a comparison of the relative abundances obtained from observations for two adjacent ionization stages of one element (for example, O/sup + +//He/sup +/ and O/sup ...