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Results 1 - 10
of
2,774
abundance
, 2000
"... Blue compact galaxies (BCG) are ideal objects in which to derive the primordial 4 He abundance because they are chemically young and have not had a significant stellar He contribution. We discuss a self-consistent method which makes use of all the brightest He I emission lines in the optical range a ..."
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Blue compact galaxies (BCG) are ideal objects in which to derive the primordial 4 He abundance because they are chemically young and have not had a significant stellar He contribution. We discuss a self-consistent method which makes use of all the brightest He I emission lines in the optical range
The lin-4 regulatory RNA controls developmental timing in Caenorhabditis elegans by blocking LIN-14 protein synthesis after the initiation of translation
- Dev. Biol
, 1999
"... lin-4 encodes a small RNA that is complementary to sequences in the 3 � untranslated region (UTR) of lin-14 mRNA and that acts to developmentally repress the accumulation of LIN-14 protein. This repression is essential for the proper timing of numerous events of Caenorhabditis elegans larval develop ..."
Abstract
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Cited by 255 (7 self)
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development. We have investigated the mechanism of lin-4 RNA action by examining the fate of lin-14 mRNA in vivo during the time that lin-4 RNA is expressed. Our results indicate that the rate of synthesis of lin-14 mRNA, its state of polyadenylation, its abundance in the cytoplasmic fraction, and its
Solar system abundances and condensation temperatures of the elements
- ApJ
"... Solar photospheric and meteoritic CI chondrite abundance determinations for all elements are summarized and the best currently available photospheric abundances are selected. The meteoritic and solar abundances of a few elements (e.g., noble gases, beryllium, boron, phosphorous, sulfur) are discusse ..."
Abstract
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Cited by 109 (0 self)
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) are discussed in detail. The photospheric abundances give mass fractions of hydrogen (X 0:7491), helium (Y 0:2377), and heavy elements (Z 0:0133), leading to Z=X 0:0177, which is lower than the widely used Z=X 0:0245 from previous compilations. Recent results from standard solar models considering helium
Fully constrained least squares linear mixture analysis for material quantification in hyperspectral imagery
- IEEE TRANS. ON GEOSCIENCE AND REMOTE SENSING
, 2001
"... Linear spectral mixture analysis (LSMA) is a widely used technique in remote sensing to estimate abundance fractions of materials present in an image pixel. In order for an LSMA-based estimator to produce accurate amounts of material abundance, it generally requires two constraints imposed on the l ..."
Abstract
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Cited by 169 (4 self)
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Linear spectral mixture analysis (LSMA) is a widely used technique in remote sensing to estimate abundance fractions of materials present in an image pixel. In order for an LSMA-based estimator to produce accurate amounts of material abundance, it generally requires two constraints imposed
CHEMICAL FRACTIONATION AND ABUNDANCES IN CORONAL PLASMA
, 2003
"... Much of modern astrophysics is grounded on the observed chemical compositions of stars and the diffuse plasma that pervades the space between stars, galaxies and clusters of galaxies. X-ray and EUV spectra of the hot plasma in the outer atmospheres of stars have demonstrated that these environments ..."
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are subject to chemical fractionation in which the abundances of elements can be enhanced and depleted by an order of magnitude or more. These coronal abundance anomalies are discussed and some of the physical mechanisms that might be responsible for producing them are examined. It is argued that coronal
Vertex component analysis: A fast algorithm to unmix hyperspectral data
- IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
, 2005
"... Given a set of mixed spectral (multispectral or hyperspectral) vectors, linear spectral mixture analysis, or linear unmixing, aims at estimating the number of reference substances, also called endmembers, their spectral signatures, and their abundance fractions. This paper presents a new method for ..."
Abstract
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Cited by 193 (16 self)
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Given a set of mixed spectral (multispectral or hyperspectral) vectors, linear spectral mixture analysis, or linear unmixing, aims at estimating the number of reference substances, also called endmembers, their spectral signatures, and their abundance fractions. This paper presents a new method
Estimation of urban vegetation abundance by spectral mixture analysis
- International Journal of Remote Sensing
"... Abstract. The spatio-temporal distribution of vegetation is a fundamental com-ponent of the urban environment that can be quanti ® ed using multispectral imagery. However, spectral heterogeneity at scales comparable to sensor reso-lution limits the utility of conventional hard classi ® cation method ..."
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Cited by 63 (5 self)
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stable, consistent estimates of vegetation fraction for both constrained and unconstrained inversions of three diVerent endmember ensembles. Quantitative validation using vegetation abundance meas-urements derived from high-resolution (2m) aerial photography shows agreement to within fractional
Estimating abundance fractions of materials in hyperspectral images by fitting a post-nonlinear mixing model
- in Proc. IEEE WHISPERS
, 2013
"... Within the area of hyperspectral data processing, nonlinear unmixing techniques have emerged as promising alternatives for overcoming the limitations of linear methods. In this pa-per, we consider the class of post-nonlinear mixing models of the partially linear form. More precisely, these composite ..."
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Cited by 5 (3 self)
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advantageously on the fractional abundances. An iterative algorithm is then derived to jointly estimate the fractional abundances and to infer the nonlinear functional term. Index Terms — Nonlinear unmixing, post-nonlinear mix-ing model, kernel methods, hyperspectral data processing
Neon Abundances from a Spitzer/IRS Survey of Wolf-Rayet Stars
, 707
"... We report on neon abundances derived from Spitzer high resolution spectral data of eight Wolf-Rayet (WR) stars using the forbidden line of [Ne III] 15.56 microns. Our targets include four WN stars of subtypes 4–7, and four WC stars of subtypes 4–7. We derive ion fraction abundances γ of Ne 2+ for th ..."
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We report on neon abundances derived from Spitzer high resolution spectral data of eight Wolf-Rayet (WR) stars using the forbidden line of [Ne III] 15.56 microns. Our targets include four WN stars of subtypes 4–7, and four WC stars of subtypes 4–7. We derive ion fraction abundances γ of Ne 2
Results 1 - 10
of
2,774
