TUNGSTEN NUCLEAR ANOMALIES IN PLANETESIMAL CORES

Use of the extinct 182 Hf- 182 W chronometer to constrain the timing of planetary accretion and differentiation rests ontheassumptionthatthesolarnebulahadhomogeneoustungstenisotopiccomposition.Here,wereportdeficiencies of � 0.1 part in 10,000 in the abundance of 184 Win group IVB iron meteorites relative to the silicate Earth. These are mostlikelyduetoincompletemixingattheplanetesimalscale(2Y4kmradiusbodies)oftheproductsof slow(s-)and rapid (r-) neutron-capture nucleosynthesis in the solar nebula. The correction that must be applied to the 182 Hf- 182 W model age of core formation in IVB irons due to the presence of these nuclear anomalies is � 0.5 Myr. Subject headingg minor planets, asteroids — nuclear reactions, nucleosynthesis, abundances — solar system: formation — stars: abundance

Semantic-Enhanced Image Clustering

Image clustering is an important and open-challenging task in computer vision. Although many methods have been proposed to solve the image clustering task, they only explore images and uncover clusters according to the image features, thus being unable to distinguish visually similar but semantically different images. In this paper, we propose to investigate the task of image clustering with the help of a visual-language pre-training model. Different from the zero-shot setting, in which the class names are known, we only know the number of clusters in this setting. Therefore, how to map images to a proper semantic space and how to cluster images from both image and semantic spaces are two key problems. To solve the above problems, we propose a novel image clustering method guided by the visual-language pre-training model CLIP, named \textbf{Semantic-Enhanced Image Clustering (SIC)}. In this new method, we propose a method to map the given images to a proper semantic space first and efficient methods to generate pseudo-labels according to the relationships between images and semantics. Finally, we propose performing clustering with consistency learning in both image space and semantic space, in a self-supervised learning fashion. The theoretical result of convergence analysis shows that our proposed method can converge at a sublinear speed. Theoretical analysis of expectation risk also shows that we can reduce the expected risk by improving neighborhood consistency, increasing prediction confidence, or reducing neighborhood imbalance. Experimental results on five benchmark datasets clearly show the superiority of our new method

An Ab Initio Description of the Mott Metal-Insulator Transition of M2_{2} Vanadium Dioxide

Using an \textit{ab initio} approach based on the GW approximation which includes strong local \textbf{k}-space correlations, the Metal-Insulator Transition of M$_2$ vanadium dioxide is broken down into its component parts and investigated. Similarly to the M$_{1}$ structure, the Peierls pairing of the M$_{2}$ structure results in bonding-antibonding splitting which stabilizes states in which the majority of the charge density resides on the Peierls chain. This is insufficient to drop all of the bonding states into the lower Hubbard band however. An antiferroelectric distortion on the neighboring vanadium chain is required to reduce the repulsion felt by the Peierls bonding states by increasing the distances between the vanadium and apical oxygen atoms, lowering the potential overlap thus reducing the charge density accumulation and thereby the electronic repulsion. The antibonding states are simultaneously pushed into the upper Hubbard band. The data indicate that sufficiently modified GW calculations are able to describe the interplay of the atomic and electronic structures occurring in Mott metal-insulator transitions.Comment: 10 Pages, 7 Figure

Article Remote Sensing of Agro-droughts in Guangdong Province of China Using MODIS Satellite Data

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Using DNA Barcoding to Identify the Genus Lolium

Seeds of the genus Lolium are difficult to identify based on morphology for morphological likeness and some physical deformation such as friction and flattening during storage and transport. DNA barcoding, a newly-established method, has been used to discriminate a variety of agricultural crops with its own advantages. In present study, DNA barcodes for the genus Lolium were investigated for the first time. DNA sequences of psbA-trnH, rbcL, atpF-atpH, and the ITS2 region were evaluated for their ability to differentiate Lolium from the related genus Festuca. As confirmed by inter-intraspecific divergence and Kimura 2 parameter analysis, the greatest divergence existed in ITS2, followed by psbA-trnH. On the contrary, rbcL and atpF-atpH possessed poor genetic variation of 0-0.0115, and was relatively difficult in discrimination of genus Lolium. For ITS2 sequence, no inter-intraspecific distance overlaps were observed and each species has a distinct barcoding gap. ITS2 could effectively discriminate all species based on a neighbor-joining tree. Thus, the ITS2 region is a candidate for DNA barcoding of Lolium

Long SAGE analysis of genes differentially expressed in the midgut and silk gland between the sexes of the silkwormBombyx mori

There are great differences in silk production efficiency and quality between the male and female domestic silkworm (Bombyx mori). Many genes act together but are differentially expressed between the sexes during silk biosynthesis. Two long serial analyses of gene expression (SAGE) libraries were constructed from the midguts and silk glands of both males and females of a sex-limited strain using 5th instar larvae, yielding in total 96,713 and 98,126 SAGE tags, respectively. Among these tags, 202 were analyzed (p < 0.05 and at least a 2.0-fold change between sexes). Overall, 69 genes were then annotated in detail and 15 tags were annotated with expressed sequence tags (ESTs) based only on the NCBI, SilkDB and long-SAGE libraries. Of these genes, only three could be ascribed to sexual disparity as described by microarray-based expression resources of day three of 5th instar in Dazao B. mori microarray database (BmMDB). The other 66 genes were considered the SAGE-extracted genes that are differentially expressed between the sexes of the whole 5th instar larvae. Among the 66 genes and 15 tags, genes (and gene families) sex-specific storage-protein 1 gene (Sp1), low molecular mass 30 kDa lipoprotein 19G1 gene (Lp-c19), serine proteinase family [serine protease precursor gene (Spp) and chymotrypsin-like serine protease gene (Ctlp)], Serpins (Spi1 and Spi2) and Ser1, and the tag 1161 (annotated EST No. BY926524), which are involved in protein digestion in the midgut, synthesis of silk and inhibition of protein disintegration in silk gland, were verified by the remarkable disparities in gene expression between the sexes. The established SAGE library would contribute to the further identification of genes related to sexual disparity in silk protein production efficiency.Key words: Bombyx mori, sexes, silk protein production efficiency, long-SAGE, differentially expressed genes

Adaptive Asymptotical Synchronization for Stochastic Complex Networks with Time-Delay and Markovian Switching

The problem of adaptive asymptotical synchronization is discussed for the stochastic complex dynamical networks with time-delay and Markovian switching. By applying the stochastic analysis approach and the M-matrix method for stochastic complex networks, several sufficient conditions to ensure adaptive asymptotical synchronization for stochastic complex networks are derived. Through the adaptive feedback control techniques, some suitable parameters update laws are obtained. Simulation result is provided to substantiate the effectiveness and characteristics of the proposed approach