29 research outputs found

    A Novel Chaotic Map and an Improved Chaos-Based Image Encryption Scheme

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    In this paper, we present a novel approach to create the new chaotic map and propose an improved image encryption scheme based on it. Compared with traditional classic one-dimensional chaotic maps like Logistic Map and Tent Map, this newly created chaotic map demonstrates many better chaotic properties for encryption, implied by a much larger maximal Lyapunov exponent. Furthermore, the new chaotic map and Arnold’s Cat Map based image encryption method is designed and proved to be of solid robustness. The simulation results and security analysis indicate that such method not only can meet the requirement of imagine encryption, but also can result in a preferable effectiveness and security, which is usable for general applications

    Effects of Epistemological and Pedagogical Beliefs on the Instructional Practices of Teachers: A Chinese Perspective

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    This study examines how the beliefs of Chinese in-service teachers regarding knowledge and knowledge acquisition influence their instructional classroom practices in junior secondary schools directly or indirectly through their conceptions of teaching and learning. The results indicate that the factor of learning effort/process is highly valued by Chinese in-service teachers in their epistemological beliefs, and that the constructivist approach is the dominant conception on teaching and learning for junior secondary school teachers.. In addition, the constructivist conception of teaching and learning is found to be positively related to three types of classroom instructional practices, whereas the traditional conception about teaching and learning is found to be only significantly and negatively linked to standard contemporary practices

    Decoding Chinese phonemes from intracortical brain signals with hyperbolic-space neural representations

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    Speech brain-computer interfaces (BCIs), which translate brain signals into spoken words or sentences, have shown significant potential for high-performance BCI communication. Phonemes are the fundamental units of pronunciation in most languages. While existing speech BCIs have largely focused on English, where words contain diverse compositions of phonemes, Chinese Mandarin is a monosyllabic language, with words typically consisting of a consonant and a vowel. This feature makes it feasible to develop high-performance Mandarin speech BCIs by decoding phonemes directly from neural signals. This study aimed to decode spoken Mandarin phonemes using intracortical neural signals. We observed that phonemes with similar pronunciations were often represented by inseparable neural patterns, leading to confusion in phoneme decoding. This finding suggests that the neural representation of spoken phonemes has a hierarchical structure. To account for this, we proposed learning the neural representation of phoneme pronunciation in a hyperbolic space, where the hierarchical structure could be more naturally optimized. Experiments with intracortical neural signals from a Chinese participant showed that the proposed model learned discriminative and interpretable hierarchical phoneme representations from neural signals, significantly improving Chinese phoneme decoding performance and achieving state-of-the-art. The findings demonstrate the feasibility of constructing high-performance Chinese speech BCIs based on phoneme decoding

    Silene sunhangii (Caryophyllaceae), a new species from China

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    Silene sunhangii, a new species of Caryophyllaceae known from only three populations in Hubei and Hunan provinces of central China, is described. Both morphological and molecular data were used to assess the taxonomic status and relationships of this species. Morphologically, S. sunhangii is most similar to S. platyphylla Franch. from which it differs most readily in having 3-veined elliptical leaves without pubescence, tasseled catacorolla, pale purple to red petals without a linear lobe or narrow tooth and lanceolate, bifid to one third. A phylogenetic analysis based on nuclear ITS region identified the new species as a well-supported, independent lineage. Our new species is nested within a grade that encompasses species representing a polyphyletic Silene sect. Physolychnis (Benth.) Bocquet. Both the genetic and morphological data support the recognition of Silene sunhangii as a distinct species, although there is inconsistency between these two datasets as to the relationships of the new species

    Taxonomic identity of Corydalis lidenii (Papaveraceae)

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    Corydalis microflora and C. lidenii are recognised as separate species in “Flora of China” and the latest plant list. However, based on the examination of type specimens and field investigations, C. lidenii is shown to be conspecific with C. microflora. As a result, C. lidenii is synonymised with C. microflora in this study

    Complete chloroplast genome sequences of Poikilospermum lanceolatum (Urticeae)

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    The complete chloroplast genome of Poikilospermum lanceolatum was sequenced using HiSeq4000 of Illumina. The length of this genome was 153, 454 bp, including a large single copy (LSC) region (84,202 bp), a small single copy (SSC) region (18,172 bp), and two inverted repeat (IR) regions (25,540 bp). The overall GC content of the genome of P. lanceolatum was 36.9%. The genome included 111 unique genes (78 protein-coding genes, 29 tRNA genes, and four rRNA genes). Phylogenetic analysis based on 67 protein-coding genes showed that Boehmerieae was sister to P. lanceolatum, with 100% bootstrap values

    Phylogeography of Parasyncalathium souliei (Asteraceae) and Its Potential Application in Delimiting Phylogeoregions in the Qinghai-Tibet Plateau (QTP)-Hengduan Mountains (HDM) Hotspot

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    Biogeographic regionalization can help to better understand diversity in biogeography, conservation, and macroecology. Historical regionalization schemes typically focus on species distributions, often rarely considering the rich context that phylogeographic information can provide. We investigated whether phylogeographic data could help to delineate floristic regions in the Qinghai-Tibet Plateau (QTP)-Hengduan Mountains (HDM) region by analyzing phylogeographic structure in the herb Parasyncalathium souliei (Asteraceae). We sequenced the plastid psbA-tmH and tmL-132 spacer regions for 417 individuals in 36 populations across the geographic range of the species. To estimate the phylogeographic history of this species, a series of population genetic, phylogenetic, molecular dating, and haplotype network analyses were conducted, as were tested for historical demographic expansions. Using occurrence data, species distribution modeling was used to estimate geographic distributions at three time points: the present, the Mid-Holocene and the Last Glacial Maximum. Significant phylogeographic structure was evident (N-ST\u3e G(ST); P \u3c 0.05) among the 37 haplotypes detected. Four major haplogroups were identified based on phylogenetic analyses. Private haplotypes were restricted to geographically distinct regions that generally corresponded to previously identified biogeographic subregions within the QTP-HDM region. Our results imply Pliocene-Pleistocene diversification of P souliei and suggest that the species may have been geographically widespread early in its history. This study may provide valuable evidence for phylogeographic regionalization using chloroplast genetic data in a common, widespread endemic species from the QTP-HDM

    Sinosenecio yangii (Asteraceae), a new species from Guizhou, China

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    A new species Sinosenecio yangii D.G. Zhang & Q. Zhou (Asteraceae, Senecioneae) from Guizhou Province, China, is described and illustrated based on its morphological characteristics and molecular evidence. It closely resembles S. confervifer and S. guangxiensis, the former in the scapigerous habit and smooth and glabrous achene surface, the latter in the calyculate involucre and purple abaxial leaf surface, and both in the shape and indumentum of leaf lamina, but differs markedly from the latter two in having fewer capitula and epappose achenes. Phylogenetic analysis based on nrITS and ndhC-trnV sequences shows that this new species belongs to the S. latouchei clade and is sister to S. guangxiensis with moderate support
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