991 research outputs found

    Magnetically tunable properties related with carriers density in self-doped La1−xMnO3/y wt %Nb-SrTiO3 heteroepitaxial junctions

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    The self-doped La1−xMnO3 (x=0.1 and 0.3) thin films deposited on Nb-doped (wt % y) SrTiO3 (y=0.05 and 0.8) crystals to form heteroepitaxial junctions have been prepared by the pulse laser deposition method. The current-voltage loops of junction were measured at several fixed magnetic fields for the temperature from 10 to 300 K. We have focused on the effects of doping level and annealing time on the magnetically tunable property of the junction. The results show that these junctions have a typical temperature-dependent rectifying characteristics and asymmetrical hysteresis. The magnetically tunable property of the junction was related with the annealing time for the self-doped La1−xMnO3−δ thin film and the doping level in the Nb-doped SrTiO3 (STON) crystal. In the self-doped La0.9MnO3/0.05-STON junction annealed at 900 °C for 5 h, the relative ratio of voltage [Vb(0)−Vb(H)] /Vb(0) is about 70% at H=6 T and T=70 K for I=0.1 mA, showing a large magnetically tunable property. These results reveal the great potential of the manganites in configuring artificial devices.published_or_final_versio

    Effect of applied magnetic field on the rectifying characteristics in self-doped La0.9MnO3/0.8 wt %Nb-SrTiO3 heteroepitaxial junctions

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    The epitaxial self-doped La0.9MnO3 thin film was deposited on a 0.8 wt %Nb-doped SrTiO3 substrate by pulse laser deposition method to form a bilayer p-n junction with an area of 8 mm2. The isothermal current-voltage loops measured from 10 to 380 K with an interval of 10 K in applied magnetic fields up to 7 T show typical temperature-dependent rectifying characteristic and asymmetrical hysteresis. The effect of magnetic field on the rectifying property is very small for the temperature above 150 K and a strong asymmetrical effect on the rectifying property below 150 K. In the low temperature region, although the diffusive voltage Vd is not affected by the applied magnetic field, the breakdown voltage Vb decreases with the increasing of magnetic field. At 10 K, the relative ratio of voltage [Vb(0)−Vb(7 T)]/Vb(0) is about 14%, showing a magnetically tunable property. These results reveal the great potential of the manganites in configuring artificial devices.published_or_final_versio

    Comparative transcriptome analyses of adzuki bean weevil (<i>Callosobruchus chinensis</i>) response to hypoxia and hypoxia/hypercapnia

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    Stored product insects show high adaption to hypoxia and hypercapnia, but the underlying mechanism is still unclear. Herein, a comparative transcriptome on 4(th) adzuki bean weevil (Callosobruchus chinensis) instar larvae was studied to clarify the response mechanisms to hypoxia (HA) and hypoxia/hypercapnia (HHA) using NextSeq500 RNA-Seq. Transcript profiling showed a significant difference in HA or HHA exposure both quantitatively and qualitatively. Compared with control, 631 and 253 genes were significantly changed in HHA and HA, respectively. Comparing HHA with HA, 1135 differentially expressed genes (DEGs) were identified. The addition of hypercapnia made a complex alteration on the hypoxia response of bean weevil transcriptome, carbohydrate, energy, lipid and amino acid metabolism were the most highly enriched pathways for genes significantly changed. In addition, some biological processes that were not significantly enriched but important were also discussed, such as immune system and signal transduction. Most of the DEGs related to metabolism both in HHA and HA were up-regulated, while the DEGs related to the immune system, stress response or signal transduction were significantly down-regulated or suppressed. This research reveals a comparatively full-scale result in adzuki bean weevil hypoxia and hypoxia/hypercapnia tolerance mechanism at transcription level, which might provide new insights into the genomic research of this species

    Aggregated impact of allowance allocation and power dispatching on emission reduction

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    Climate change has become one of the most important issues for the sustainable development of social well-being. China has made great efforts in reducing CO2 emissions and promoting clean energy. Pilot Emission Trading Systems (ETSs) have been launched in two provinces and five cities in China, and a national level ETS will be implemented in the third quarter of 2017, with preparations for China’s national ETS now well under way. In the meantime, a new round of China’s electric power system reform has entered the implementation stage. Policy variables from both electricity and emission markets will impose potential risks on the operation of generation companies (GenCos). Under this situation, by selecting key variables in each domain, this paper analyzes the combined effects of different allowance allocation methods and power dispatching models on power system emission. Key parameters are set based on a provincial power system in China, and the case studies are conducted based on dynamic simulation platform for macro-energy systems (DSMES) software developed by the authors. The selected power dispatching models include planned dispatch, energy saving power generation dispatch and economic dispatch. The selected initial allowance allocation methods in the emission market include the grandfathering method based on historical emissions and the benchmarking method based on actual output. Based on the simulation results and discussions, several policy implications are highlighted to help to design an effective emission market in China

    Genetic Variation of HvCBF Genes and Their Association with Salinity Tolerance in Tibetan Annual Wild Barley

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    The evaluation of both the genetic variation and the identification of salinity tolerant accessions of Tibetan annual wild barley (hereafter referred to as Tibetan barley) (Hordeum vulgare L. ssp. Spontaneum and H. vulgare L. ssp. agriocrithum) are essential for discovering and exploiting novel alleles involved in salinity tolerance. In this study, we examined tissue dry biomass and the Na+ and K+ contents of 188 Tibetan barley accessions in response to salt stress. We investigated the genetic variation of transcription factors HvCBF1, HvCBF3 and HvCBF4 within these accessions, conducting association analysis between these three genes and the respective genotypic salt tolerance. Salt stress significantly reduced shoot and root dry weight by 27.6% to 73.1% in the Tibetan barley lines. HvCBF1, HvCBF3 and HvCBF4 showed diverse sequence variation in amplicon as evident by the identification of single nucleotide polymorphisms (SNPs) and 3, 8 and 13 haplotypes, respectively. Furthermore, the decay of Linkage disequilibrium (LD) of chromosome 5 was 8.9 cM (r2<0.1). Marker bpb-4891 and haplotype 13 (Ps 610) of the HvCBF4 gene were significantly (P<0.05) and highly significantly (P<0.001) associated with salt tolerance. However, HvCBF1 and HvCBF3 genes were not associated with salinity tolerance. The accessions from haplotype 13 of the HvCBF4 gene showed high salinity tolerance, maintaining significantly lower Na+/K+ ratios and higher dry weight. It is thus proposed that these Tibetan barley accessions could be of value for enhancing salinity tolerance in cultivated barley

    Observation of a ppb mass threshoud enhancement in \psi^\prime\to\pi^+\pi^-J/\psi(J/\psi\to\gamma p\bar{p}) decay

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    The decay channel ψπ+πJ/ψ(J/ψγppˉ)\psi^\prime\to\pi^+\pi^-J/\psi(J/\psi\to\gamma p\bar{p}) is studied using a sample of 1.06×1081.06\times 10^8 ψ\psi^\prime events collected by the BESIII experiment at BEPCII. A strong enhancement at threshold is observed in the ppˉp\bar{p} invariant mass spectrum. The enhancement can be fit with an SS-wave Breit-Wigner resonance function with a resulting peak mass of M=186113+6(stat)26+7(syst)MeV/c2M=1861^{+6}_{-13} {\rm (stat)}^{+7}_{-26} {\rm (syst)} {\rm MeV/}c^2 and a narrow width that is Γ<38MeV/c2\Gamma<38 {\rm MeV/}c^2 at the 90% confidence level. These results are consistent with published BESII results. These mass and width values do not match with those of any known meson resonance.Comment: 5 pages, 3 figures, submitted to Chinese Physics

    Observation of the electromagnetic doubly OZI-suppressed decay J/ψϕπ0J/\psi \rightarrow \phi \pi^{0}

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    Using a sample of 1.311.31 billion J/ψJ/\psi events accumulated with the BESIII detector at the BEPCII collider, we report the observation of the decay J/ψϕπ0J/\psi \rightarrow \phi\pi^{0}, which is the first evidence for a doubly Okubo-Zweig-Iizuka suppressed electromagnetic J/ψJ/\psi decay. A clear structure is observed in the K+KK^{+} K^{-} mass spectrum around 1.02 GeV/c2c^2, which can be attributed to interference between J/ψϕπ0J/\psi \rightarrow \phi\pi^{0} and J/ψK+Kπ0J/\psi \rightarrow K^{+}K^{-}\pi^{0} decays. Due to this interference, two possible solutions are found. The corresponding measured values of the branching fraction of J/ψϕπ0J/\psi \to \phi\pi^{0} are [2.94±0.16(stat.)±0.16(syst.)]×106[2.94 \pm 0.16\text{(stat.)} \pm 0.16\text{(syst.)}] \times 10^{-6} and [1.24±0.33(stat.)±0.30(syst.)]×107[1.24 \pm 0.33\text{(stat.)} \pm 0.30\text{(syst.)}] \times 10^{-7}.Comment: 7 pages, 4 figures, published in Phys. Rev.

    Transcriptome Analysis of the Brown Planthopper Nilaparvata lugens

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    BACKGROUND: The brown planthopper (BPH) Nilaparvata lugens (Stål) is one of the most serious insect pests of rice in Asia. However, little is known about the mechanisms responsible for the development, wing dimorphism and sex difference in this species. Genomic information for BPH is currently unavailable, and, therefore, transcriptome and expression profiling data for this species are needed as an important resource to better understand the biological mechanisms of BPH. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we performed de novo transcriptome assembly and gene expression analysis using short-read sequencing technology (Illumina) combined with a tag-based digital gene expression (DGE) system. The transcriptome analysis assembles the gene information for different developmental stages, sexes and wing forms of BPH. In addition, we constructed six DGE libraries: eggs, second instar nymphs, fifth instar nymphs, brachypterous female adults, macropterous female adults and macropterous male adults. Illumina sequencing revealed 85,526 unigenes, including 13,102 clusters and 72,424 singletons. Transcriptome sequences larger than 350 bp were subjected to Gene Orthology (GO) and KEGG Orthology (KO) annotations. To analyze the DGE profiling, we mainly compared the gene expression variations between eggs and second instar nymphs; second and fifth instar nymphs; fifth instar nymphs and three types of adults; brachypterous and macropterous female adults as well as macropterous female and male adults. Thousands of genes showed significantly different expression levels based on the various comparisons. And we randomly selected some genes to confirm their altered expression levels by quantitative real-time PCR (qRT-PCR). CONCLUSIONS/SIGNIFICANCE: The obtained BPH transcriptome and DGE profiling data provide comprehensive gene expression information at the transcriptional level that could facilitate our understanding of the molecular mechanisms from various physiological aspects including development, wing dimorphism and sex difference in BPH

    Echinococcus multilocularis and Echinococcus shiquicus in a small mammal community on the eastern Tibetan Plateau : host species composition, molecular prevalence, and epidemiological implications

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    Background The eastern part of the Tibetan Plateau is now recognized as an endemic region with the highest reported human infection rates in the world of human alveolar echinococcosis (AE) caused by Echinococcus multilocularis. Existing epidemiological studies on AE have mainly focused on the synanthropic environment, while basic parasitological and ecological aspects in wildlife host species remain largely unknown, especially for small mammal hosts. Therefore, we examined small mammal host species composition, occurrence, and the prevalence of both E. multilocularis and E. shiquicus in Shiqu County (Sichuan Province, China), eastern Tibetan Plateau. Results In total, 346 small mammals from five rodent and one pika species were trapped from four randomly set 0.25 ha square plots. Two vole species, Lasiopodomys fuscus (n = 144) and Microtus limnophilus (n = 44), and the plateau pika (Ochotona curzoniae) (n = 135), were the three most-dominant species trapped. Although protoscoleces of E. multilocularis and E. shiquicus were only observed in L. fuscus and O. curzoniae, respectively, cox1 and nad1 gene DNA of E. shiquicus was detected in all the small mammal species except for Neodon irene, whereas E. multilocularis was detected in the three most-dominant species. The overall molecular prevalence of Echinococcus species was 5.8 (95% CI: 3.3–8.2%) ~ 10.7% (95% CI: 7.4–14.0%) (the conservative prevalence to the maximum prevalence with 95% CI in parentheses), whereas for E. multilocularis it was 4.3 (95% CI: 2.2–6.5%) ~ 6.7% (95% CI: 4.0–9.3%), and 1.5 (95% CI: 0.2–2.7%) ~ 4.1% (95% CI: 2.0–6.1%) for E. shiquicus. The prevalence of both E. multilocularis and E. shiquicus, was significantly higher in rodents (mainly voles) than in pikas. Phylogenetic analyses revealed that Echinococcus haplotypes of cox1 from small mammal hosts were actively involved in the sylvatic and anthropogenic transmission cycles of E. multilocularis in the eastern Tibetan Plateau. Conclusions In contrast to previous studies, the current results indicated that rodent species, rather than pikas, are probably more important natural intermediate hosts of E. multilocularis and E. shiquicus in the eastern Tibetan Plateau. Thus, understanding interspecific dynamics between rodents and pikas is essential to studies of the echinococcosis transmission mechanism and human echinococcosis prevention in local communities. Keywords: Echinococcus multilocularis, E. shiquicus, Small mammal Prevalence, Tibetan Platea
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