Abstract
We present the second release of value-added catalogues of the LAMOST Spectroscopic Survey of the Galactic Anticentre (LSS-GAC DR2). The catalogues present values of radial velocity Vr, ...atmospheric parameters – effective temperature Teff, surface gravity log g, metallicity Fe/H, α-element to iron (metal) abundance ratio α/Fe (α/M), elemental abundances C/H and N/H and absolute magnitudes MV and $M_{K_{\rm s}}$ deduced from 1.8 million spectra of 1.4 million unique stars targeted by the LSS-GAC since 2011 September until 2014 June. The catalogues also give values of interstellar reddening, distance and orbital parameters determined with a variety of techniques, as well as proper motions and multiband photometry from the far-UV to the mid-IR collected from the literature and various surveys. Accuracies of radial velocities reach 5 km s−1 for the late-type stars, and those of distance estimates range between 10 and 30 per cent, depending on the spectral signal-to-noise ratios. Precisions of Fe/H, C/H and N/H estimates reach 0.1 dex, and those of α/Fe and α/M reach 0.05 dex. The large number of stars, the contiguous sky coverage, the simple yet non-trivial target selection function and the robust estimates of stellar radial velocities and atmospheric parameters, distances and elemental abundances make the catalogues a valuable data set to study the structure and evolution of the Galaxy, especially the solar-neighbourhood and the outer disc.
Accurate determination of stellar atmospheric parameters and elemental abundances is crucial for Galactic archaeology via large-scale spectroscopic surveys. In this paper, we estimate stellar ...atmospheric parameters -- effective temperature T sub( eff), surface gravity log g and metallicity Fe/H, absolute magnitudes M sub( V) and M sub( Ks), ...-element to metal (and iron) abundance ratio .../M (and .../Fe), as well as carbon and nitrogen abundances C/H and N/H from the Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) spectra with a multivariate regression method based on kernel-based principal component analysis, using stars in common with other surveys (Hipparcos, Kepler, Apache Point Observatory Galactic Evolution Experiment) as training data sets. Both internal and external examinations indicate that given a spectral signal-to-noise ratio (SNR) better than 50, our method is capable of delivering stellar parameters with a precision of ~100 K for T sub( eff), ~0.1 dex for log g, 0.3-0.4 mag for M sub( V) and M sub( Ks), 0.1 dex for Fe/H, C/H and N/H, and better than 0.05 dex for .../M (.../Fe). The results are satisfactory even for a spectral SNR of 20. The work presents first determinations of C/H and N/H abundances from a vast data set of LAMOST, and, to our knowledge, the first reported implementation of absolute magnitude estimation directly based on a vast data set of observed spectra. The derived stellar parameters for millions of stars from the LAMOST surveys will be publicly available in the form of value-added catalogues. (ProQuest: ... denotes formulae/symbols omitted.)
Sorbitol dehydrogenase (SDH) catalyses the reversible oxidation of sorbitol, xylitol and ribitol to their corresponding ketoses. In this study, we investigated the expression and role of Arabidopsis ...SDH in salt and osmotic stress tolerance, and abscisic acid (ABA) response. The expression patterns of SDH were investigated using transgenic Arabidopsis plants expressing beta-glucuronidase (GUS) under control of the promoter with the first intron of SDH. qRT-PCR and histochemical assay of GUS activity were used to study SDH expression regulation by ABA, salt and osmotic stress. SDH-overexpression lines of Arabidopsis were used to investigate the role of SDH in salt and osmotic stress, and ABA response. Arabidopsis SDH was predominantly expressed in source organs such as green cotyledons, fully expanded leaves and sepals, especially in vascular tissues of theses organs. SDH expression was inhibited by NaCl and mannitol treatments. Seed germination and post-germination growth of SDH-overexpressing lines exhibited decreased sensitivity to salt and osmotic stress compared to WT plants. The transcript of SDH was induced by ABA. Overexpression of SDH decreased sensitivity to ABA during seed germination and post-germination growth. Expression of AAO3 increased but ABI5 and MYB2 decreased in SDH-overexpressing lines after ABA treatment. This study demonstrates that expression of SDH is regulated by ABA, salt and osmotic stress. SDH functions in plant tolerance to salt and osmotic stress, and ABA response via specific regulating gene expression of ABA synthesis and signalling in Arabidopsis.
The origin of the deformation in metallic glasses is attributed to rearrangements of atoms in some structurally weak spots behaving as flow units, which are associated with free volumes. In the ...present study, Xe-ion beam is used to manipulate the free-volume fraction, and influence on the mechanical behavior of a Zr-based metallic glass. The irradiation at low dosages can change the structure by increasing the free volume, and by homogenising the distribution of free volume. The increase in the free-volume fraction is equivalent to the increase in the deformation temperature, thus resulting in the decrease in the yield strength. The analysis of stochastic strain burst size in the metallic glass irradiated at different dosages indicates that the strain burst depends on the yield strength and homogeneity of the glassy phase. The results of this study highlight the fact that the quantitative manipulation of the homogeneity and the amount of free volumes can be achieved through low-dose ion irradiation, which can modify the mechanical behavior of metallic glasses.
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Summary
Clonostachys rosea is a promising saprophytic filamentous fungus that belongs to phylum Ascomycota. Clonostachys rosea is widespread around the world and exists in many kinds of habitats, ...with the highest frequency in soil. As an excellent mycoparasite, C. rosea exhibits strong biological control ability against numerous fungal plant pathogens, nematodes and insects. These behaviours are based on the activation of multiple mechanisms such as secreted cell‐wall‐degrading enzymes, production of antifungal secondary metabolites and induction of plant defence systems. Besides having significant biocontrol activity, C. rosea also functions in the biodegradation of plastic waste, biotransformation of bioactive compounds, as a bioenergy sources and in fermentation. This mini review summarizes information about the biology and various applications of C. rosea and expands on its possible uses.
Modeling approach to permeability especially anisotropic permeability of coal in front of working face is of significance for gas extraction in coal mining. Considering three-dimensional stress ...condition and multi-field influence, in this study, an anisotropic permeability model was suggested for coal in front of working face. The anisotropic permeability was assumed to be controlled by the directional fracture strain under the condition of multi-field influence caused by effective stress, adsorption-desorption and thermal stress. The directional fracture strain induced by effective stress was governed by the generalized Hooke constitutive model. Based on the matrix-fracture interaction, the constitutive model of directional fracture strain induced by adsorption-desorption was established from the improved Langmuir equation. Assuming that the coal matrix was connected by the matrix bridge, the constitutive model of directional fracture strain induced by thermal stress was constructed by proposing the thermal internal swelling coefficient. Consequently, a new anisotropic coal permeability model was developed based on the directional fracture strain under the influence factor of stress, gas sorption and temperature. Moreover, the new permeability model was verified by laboratory tests under different effective stresses, gas pressures, temperatures and their combined influence. The theoretical results of proposed anisotropic permeability model may provide a better understanding of permeability evolution in multi-field coupling geological environment during coal mining.
Universal brain signature of proficient reading Rueckl, Jay G.; Paz-Alonso, Pedro M.; Molfese, Peter J. ...
Proceedings of the National Academy of Sciences - PNAS,
12/2015, Letnik:
112, Številka:
50
Journal Article
Recenzirano
Odprti dostop
We propose and test a theoretical perspective in which a universal hallmark of successful literacy acquisition is the convergence of the speech and orthographic processing systems onto a common ...network of neural structures, regardless of how spoken words are represented orthographically in a writing system. During functional MRI, skilled adult readers of four distinct and highly contrasting languages, Spanish, English, Hebrew, and Chinese, performed an identical semantic categorization task to spoken and written words. Results from three complementary analytic approaches demonstrate limited language variation, with speech–print convergence emerging as a common brain signature of reading proficiency across the wide spectrum of selected languages, whether their writing system is alphabetic or logographic, whether it is opaque or transparent, and regardless of the phonological and morphological structure it represents.
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