The complete nucleotide sequences of the chloroplast (cp) and mitochondrial (mt) genomes of resurrection plant Boea hygrometrica (Bh, Gesneriaceae) have been determined with the lengths of 153,493 bp and 510,519 bp, respectively. The smaller chloroplast genome contains more genes (147) with a 72% coding sequence, and the larger mitochondrial genome have less genes (65) with a coding faction of 12%. Similar to other seed plants, the Bh cp genome has a typical quadripartite organization with a conserved gene in each region. The Bh mt genome has three recombinant sequence repeats of 222 bp, 843 bp, and 1474 bp in length, which divide the genome into a single master circle (MC) and four isomeric molecules. Compared to other angiosperms, one remarkable feature of the Bh mt genome is the frequent transfer of genetic material from the cp genome during recent Bh evolution. We also analyzed organellar genome evolution in general regarding genome features as well as compositional dynamics of sequence and gene structure/organization, providing clues for the understanding of the evolution of organellar genomes in plants. The cp-derived sequences including tRNAs found in angiosperm mt genomes support the conclusion that frequent gene transfer events may have begun early in the land plant lineage.

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The need for valuable land has encouraged reclamation in coastal areas worldwide in the past decades. Land reclamation can alter the groundwater quality in coastal aquifers. The purpose of this study is to identify the effect of land reclamation on groundwater chemistry, especially the major ions, and heavy metals on Zhoushan Island, China. The subsurface media on the island is composed of two layers, i.e., an upper infill layer and an underlain clay layer. The upper layer is previously ocean and filled with various materials. The clay layer is the original marine sediment. The dominated Na and Cl ions in groundwater illustrate high salinity sources of groundwater in the subsurface of the reclaimed land. A mixing trend between seawater and river water of the groundwater in infill layer is also detected based on the ratios of Cl and Br. Though the heavy metal concentrations (Cd, Cr, Zn and Hg) are high in marine sediments, no significant releasing trends in the groundwater are detected in a short-term after reclamation (based on standard GB18668). Meanwhile, Fe-III concentrations in the aquifer have a strong correlation with precipitation events. Column desorption experiments and simulations indicate the Cd and Cr release from the sediment would pose a health risk when the groundwater in the infill layer being gradually flushed by fresh water. These results provide a foundation for the prediction of groundwater quality and are helpful for the future water management in a newly reclaimed land.

Direction-of-arrival (DOA) estimation is a fundamental problem in many signal processing. Recently, a variety of sparsity-aware methods have been proposed for DOA estimation. The discrimination of grid in these methods often suffers from grid mismatch problem, which degrades the performance of DOA estimation, when the true unknown DOAs are not on the potential angular grids. To deal with grid mismatch problem in conventional sparsity-based methods, a novel off-grid model is proposed via Taylor interpolation that jointly estimates the sparse signals and grid offset parameters, using a family of successive nonconvex sparsity approximation penalties on the sparse signals. Then an iterative alternating optimization strategy is utilized to tackle this nonconvex problem with respect to sparse signals and grid offset parameters, and the proposed algorithm is solved by the proximal splitting algorithm in each iteration, where the optimization problem is split into two parts: sparsity and projection. The proposed framework in this paper is universal and also can be extended to other off-grid sparsity-based algorithms. The extensive simulations are conducted to verify that the proposed method achieves superior resolution and more accurate DOA estimation performance than other conventional sparsity-based method and the state-of-the-art off-grid methods in many cases of practical interest. INDEX TERMS Direction-of-arrival (DOA) estimation, off-grid model, sparsity approximation, proximal algorithm, iterative approach.

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