Results 11 to 20 of about 945 (188)
Chloroplast Genome Evolution and Species Identification of Styrax (Styracaceae). [PDF]
Biomed Res Int, 2022 The genus Styrax L. consists of approximately 130 species distributed in the Americas, eastern Asia, and the Mediterranean region. The phylogeny and evolutionary history of this genus are not clear. Knowledge of the phylogenetic relationships and the method for species identification will be critical for the evolution of this genus.
Song Y, Zhao W, Xu J, Li M, Zhang Y.
europepmc +2 more sources
Collineations in Generalized Spaces [PDF]
Proceedings of the American Mathematical Society, 1951 Jack Levine
openalex +2 more sources
PROJECTIVE COLLINEATIONS AS PRODUCTS OF CYCLIC COLLINEATIONS [PDF]
Demonstratio Mathematica, 1979 Krzysztof Witczyúski
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Classical and Quantum Gravity, 2020 What is the asymptotic future of a scalar-field model if the assumption of isotropy is relaxed in generic, homogeneous space-times with general relativity? This paper is a continuation of our previous work on Bianchi cosmologies with a $p$-form field (where $p\,\in\,\{1,3\}$)---or equivalently: an inhomogeneous, mass-less scalar gauge field with a ...
Ben David Normann, Sigbjørn Hervik
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WEYL COLLINEATIONS THAT ARE NOT CURVATURE COLLINEATIONS [PDF]
International Journal of Modern Physics D, 2005 Though the Weyl tensor is a linear combination of the curvature tensor, Ricci tensor and Ricci scalar, it does not have all and only the Lie symmetries of these tensors since it is possible, in principle, that "asymmetries cancel." Here we investigate if, when and how the symmetries can be different.
Asghar Qadir +3 more
openaire +5 more sources
A 1 × 48 large‐scale multi‐mode fibre optical switch
IET Optoelectronics, Volume 16, Issue 6, Page 253-256, December 2022., 2022 Abstract A 1 × 48 large‐scale multi‐mode fibre (MMF) optical switch driven by a stepper motor is reported. The insertion loss is <1.42 dB, which can be further reduced to 1.02 dB after optimisation. With the employment of a corner cube prism in the optics, the device is characterised by good repeatability of <±0.01 dB.
Zhentian Shan, Zhujun Wan, Zhixiang Luo
wiley +1 more source
African Journal of Ecology, Volume 60, Issue 4, Page 1133-1142, December 2022., 2022 Abstract Artemisia afra was identified as an encroaching shrub in the Klipriviersberg Nature Reserve (KNR). Ecological factors that influence the encroachment of A. afra and its population structure were unknown, making it difficult to monitor and control the spread of the plant.
Kgalalelo T. A. Setshedi +2 more
wiley +1 more source
The minimum degree of minimal Ramsey graphs for cliques
Bulletin of the London Mathematical Society, Volume 54, Issue 5, Page 1827-1838, October 2022., 2022 Abstract We prove that sr(Kk)=O(k5r5/2)$s_r(K_k) = O(k^5 r^{5/2})$, where sr(Kk)$s_r(K_k)$ is the Ramsey parameter introduced by Burr, Erdős and Lovász in 1976, which is defined as the smallest minimum degree of a graph G$G$ such that any r$r$‐colouring of the edges of G$G$ contains a monochromatic Kk$K_k$, whereas no proper subgraph of G$G$ has this ...
John Bamberg +2 more
wiley +1 more source
ρ‐Einstein Solitons on Warped Product Manifolds and Applications
Journal of Mathematics, Volume 2022, Issue 1, 2022., 2022 The purpose of this research is to investigate how a ρ‐Einstein soliton structure on a warped product manifold affects its base and fiber factor manifolds. Firstly, the pertinent properties of ρ‐Einstein solitons are provided. Secondly, numerous necessary and sufficient conditions of a ρ‐Einstein soliton warped product manifold to make its factor ρ ...
Nasser Bin Turki +5 more
wiley +1 more source
Conformally Flat Pseudoprojective Symmetric Spacetimes in fR,G Gravity
Advances in Mathematical Physics, Volume 2022, Issue 1, 2022., 2022 Sufficient conditions on a pseudoprojective symmetric spacetime (PPS)n whose Ricci tensor is of Codazzi type to be either a perfect fluid or Einstein spacetime are given. Also, it is shown that a (PPS)n is Einstein if its Ricci tensor is cyclic parallel. Next, we illustrate that a conformally flat (PPS)n spacetime is of constant curvature.
Uday Chand De +4 more
wiley +1 more source