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A new species of the genus Leptobrachella, Leptobrachella damingshanensis sp. nov. is described from central Guangxi, China, based on morphological, molecular, and acoustic data. Phylogenetic analyses using a 16S rRNA gene fragment indicated that the new species formed an independent clade close to L. nahangensis and L. nyx. However, the new species differs from all known congeners based on a combination of the following characters: medium size (snout-vent length (SVL) 33.6–34.4 mm in males); pair of distinct jacinth humeral glands on proximal thigh area; rough dorsal skin with sparse jacinth tubercles and several short longitudinal ridges; creamy white ventral surface with small, creamy white glands on throat, chest, belly, and ventral surfaces of thighs, becoming more concentrated near lateral margin; webbing and lateral fringes absent on fingers, toes with rudimentary webbing and narrow lateral fringes; flanks with small irregular black spots; iris bicolored, upper half copper, fading to silver in lower half. Uncorrected p-distances were greater than 4.7% between Leptobrachella damingshanensis sp. nov. and all homologous DNA sequences available for the 16S rRNA gene. The new species is only known to occur in the Damingshan National Nature Reserve, where it inhabits montane evergreen forests between 1 000–1 200 m.

The reciprocal degree resistance distance index of a connected graph G is defined as RDRG=∑u,v⊆VGdGu+dGv/rGu,v, where rGu,v is the resistance distance between vertices u and v in G. Let Un denote the set of unicyclic graphs with n vertices. We study the graph with maximum reciprocal degree resistance distance index among all graphs in Un and characterize the corresponding extremal graph.

In this paper, in terms of Wiener index, hyper-Wiener index and Harary index, we first give some sufficient conditions for a nearly balance bipartite graph with given minimum degree to be traceable. Secondly, we establish some conditions for a k-connected graph to be Hamilton-connected and traceable for every vertex, respectively.

Let G be a simple graph and A(G) be the adjacency matrix of G. The eigenvalues of A(G) are referred to as the eigenvalues of G. In this paper, we characterize the graphs with the minimal least eigenvalue among all graphs whose complements are connected and have only two pendent vertices.

In this paper, we establish sufficient conditions for a connected claw-free graph to be traceable in terms of the signless Laplacian spectral radius of the graph or Laplacian eigenvalues of its complements, respectively.

Let S n c be the set of all connected graph each of which is a complement of an n -vertex unicyclic graph. Li and Wang (2012) determined the graphs with the least signless Laplacian eignvalue among all the graphs of the complements of n -vertex trees. In this paper, as a continuance of it, the unique graph among S n c which minimizes the least signless Laplacian eigenvalue is identified.

The hyper-Wiener index WW(G) is defined as with the summation going over all pairs of vertices in G. In this paper, we determine graphs with the minimum hyper-Wiener index among all the unicyclic graphs with n vertices and k pendent vertices.

Let G be a simple graph and let Q (G) be the signless Laplacian matrix of G. In this paper we obtain some results on the spectral perturbation of the matrix Q (G) under an edge addition or an edge contraction.

In this paper we establish some spectral conditions for a graph to be Hamilton-connected in terms of the spectral radius of the adjacency matrix or the signless Laplacian of the graph or its complement. For the existence of Hamiltonian paths or cycles in a graph, we also give a sufficient condition by the signless Laplacian spectral radius.

T0 understand the population distribution, species abundance and habitats requirement of a medicinal animal, Centropus sinensis, in Guangxi Province.Line transect methods were used to census population number and habitat types in 18 counties or cities of Guangxi.Centropus sinensis distributed in all study area, with a higher population density in the south than in the north. Among seven habitat types, the species preferred living in forest-farmland ecotone, while seldom in broad-leaves forest or plantations.The results of habitat preference show an advantage to the population recovering for forest-farmland ecotone commonly existing in Guangxi Province. But the speed of population recovering is slowly under illegal hunting pressure. More attention should be paid to protect this species.

In this paper we get a structural property for a graph having the minimal least eigenvalue among all graphs of fixed order and given chromatic number, and characterize such graphs under the condition that the chromatic number is not larger than half the order of the graph. As a result, we obtain a lower bound on the least eigenvalue in terms of the chromatic number, and an upper bound on the chromatic number in terms of the least eigenvalue of a graph.