2,228 research outputs found
De facto currency baskets of China and East Asian economies: The rising weights
We employ Bayesian method to estimate a time-varying coefficient version of the de facto currency basket model of Frankel and Wei (2007) for the RMB of China, using daily data from February 2005 to July 2011. We estimate jointly the implicit time-varying weights of all 11 currencies in the reference basket announced by the Chinese government. We find the dollar weight has been reduced and sometimes significantly smaller than one, but there is no evidence of systematic operation of a currency basket with discernable pattern of significant weights on other currencies. During specific periods, the reduced dollar weight has not been switched to other major international currencies, but to some East Asian currencies, which is hard to explain by trade importance to or trade competition with China. We examine currency baskets of these East Asian Economies, including major international currencies and the RMB in their baskets. We find an evident tendency of Malaysia and Singapore to increase the weights of RMB in their own currency baskets, and a steadily and significantly positive weight of RMB in the basket of Thailand. These evidences suggest that, the positive weights of some East Asian currencies in RMB currency basket during specific periods largely reflect the fact that these East Asia economies have been systematically placing greater weights on RMB under the new regime of RMB exchange rate.RMB currency basket; time-varying regressions; East Asia; China; US
Three-dimensional structure of the milky way dust: modeling of LAMOST data
We present a three-dimensional modeling of the Milky Way dust distribution by
fitting the value-added star catalog of LAMOST spectral survey. The global dust
distribution can be described by an exponential disk with scale-length of 3,192
pc and scale height of 103 pc. In this modeling, the Sun is located above the
dust disk with a vertical distance of 23 pc. Besides the global smooth
structure, two substructures around the solar position are also identified. The
one located at and is
consistent with the Gould Belt model of \citet{Gontcharov2009}, and the other
one located at and is
associated with the Camelopardalis molecular clouds.Comment: 15 pages, 6 figure, accepted by Ap
Transmission of H7N9 influenza virus in mice by different infective routes.
BackgroundOn 19 February 2013, the first patient infected with a novel influenza A H7N9 virus from an avian source showed symptoms of sickness. More than 349 laboratory-confirmed cases and 109 deaths have been reported in mainland China since then. Laboratory-confirmed, human-to-human H7N9 virus transmission has not been documented between individuals having close contact; however, this transmission route could not be excluded for three families. To control the spread of the avian influenza H7N9 virus, we must better understand its pathogenesis, transmissibility, and transmission routes in mammals. Studies have shown that this particular virus is transmitted by aerosols among ferrets.MethodsTo study potential transmission routes in animals with direct or close contact to other animals, we investigated these factors in a murine model.ResultsViable H7N9 avian influenza virus was detected in the upper and lower respiratory tracts, intestine, and brain of model mice. The virus was transmissible between mice in close contact, with a higher concentration of virus found in pharyngeal and ocular secretions, and feces. All these biological materials were contagious for naïve mice.ConclusionsOur results suggest that the possible transmission routes for the H7N9 influenza virus were through mucosal secretions and feces
The mouse and ferret models for studying the novel avian-origin human influenza A (H7N9) virus.
BackgroundThe current study was conducted to establish animal models (including mouse and ferret) for the novel avian-origin H7N9 influenza virus.FindingsA/Anhui/1/2013 (H7N9) virus was administered by intranasal instillation to groups of mice and ferrets, and animals developed typical clinical signs including body weight loss (mice and ferrets), ruffled fur (mice), sneezing (ferrets), and death (mice). Peak virus shedding from respiratory tract was observed on 2 days post inoculation (d.p.i.) for mice and 3-5 d.p.i. for ferrets. Virus could also be detected in brain, liver, spleen, kidney, and intestine from inoculated mice, and in heart, liver, and olfactory bulb from inoculated ferrets. The inoculation of H7N9 could elicit seroconversion titers up to 1280 in ferrets and 160 in mice. Leukopenia, significantly reduced lymphocytes but increased neutrophils were also observed in mouse and ferret models.ConclusionsThe mouse and ferret model enables detailed studies of the pathogenesis of this illness and lay the foundation for drug or vaccine evaluation
The luminescence dating chronology of a deep core from Bosten Lake (NW China) in arid central Asia reveals lake evolution over the last 220 ka
Native defects in tetradymite Bi2(TexSe3−x) topological insulators
Formation energies of native defects in Bi2(TexSe3−x), with comparison to ideal Bi2Te2S, are calculated in density-functional theory to assess transport properties. Bi2Se3 is found to be n type for both Bi- and Se-rich growth conditions, while Bi2Te3 changes fromn to p type going from Te- to Bi-rich conditions, as observed. Bi2Te2Se and Bi2Te2S are generally n type, explaining observed heavily doped n-type behavior in most samples. A (0/−) transition level at 16 meV above valence-band maximum for Bi on Te antisites in Bi2Te2Se is related to the observed thermally active transport gap causing a p-to-n transition at low temperature. Bi2(TexSe3−x) with x\u3e2 are predicted to have high bulk resistivity due to effective carrier compensation when approaching the n-to-pcrossover. Predicted behaviors are confirmed from characterization of our grown single crystals
Development of MnBi permanent magnet: Neutron diffraction of MnBi powder
MnBi attracts great attention in recent years for its great potential as permanent magnetmaterials. MnBi phase is difficult to obtain because of the rather drastic peritectic reaction between Mn and Bi. In this paper, we report our effort on synthesizing high purity MnBi compound using conventional powder metallurgical approaches. Neutron diffraction was carried out to investigate the crystal and nuclear structure of the obtained powder. The result shows that the purity of the obtained powder is about 91 wt. % at 300 K, and the magnetic moment of the Mn atom in MnBi lattice is 4.424 and 4.013 μ B at 50 K and 300 K, respectively
Large-scale collection and annotation of gene models for date palm (Phoenix dactylifera, L.)
The date palm (Phoenix dactylifera L.), famed for its sugar-rich fruits (dates) and cultivated by humans since 4,000 B.C., is an economically important crop in the Middle East, Northern Africa, and increasingly other places where climates are suitable. Despite a long history of human cultivation, the understanding of P. dactylifera genetics and molecular biology are rather limited, hindered by lack of basic data in high quality from genomics and transcriptomics. Here we report a large-scale effort in generating gene models (assembled expressed sequence tags or ESTs and mapped to a genome assembly) for P. dactylifera, using the long-read pyrosequencing platform (Roche/454 GS FLX Titanium) in high coverage. We built fourteen cDNA libraries from different P. dactylifera tissues (cultivar Khalas) and acquired 15,778,993 raw sequencing reads—about one million sequencing reads per library—and the pooled sequences were assembled into 67,651 non-redundant contigs and 301,978 singletons. We annotated 52,725 contigs based on the plant databases and 45 contigs based on functional domains referencing to the Pfam database. From the annotated contigs, we assigned GO (Gene Ontology) terms to 36,086 contigs and KEGG pathways to 7,032 contigs. Our comparative analysis showed that 70.6 % (47,930), 69.4 % (47,089), 68.4 % (46,441), and 69.3 % (47,048) of the P. dactylifera gene models are shared with rice, sorghum, Arabidopsis, and grapevine, respectively. We also assigned our gene models into house-keeping and tissue-specific genes based on their tissue specificity. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11103-012-9924-z) contains supplementary material, which is available to authorized users
A design visualization machine : an agile prototype for architectural plans on a finite grid
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Architecture, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (p. 64-65).This thesis project proposes a rapid visualization machine that can produce agile prototypes of simple architectural plans on a finite grid system. While various visualization systems to demonstrate instantaneous three dimensional form generations have been implemented recently by automobile industries and artists, a small scale visualization machine for architectural planning purposes has not been tested. Through careful analysis of the minimalist architectural plans of Ludwig Mies van der Rohe and research into the schematic plans of Palladian villas, it was determined that 1) fundamental structural components are the column and the wall, and 2) simple architectural plans can be well represented by a finite grid system on which those components are laid out. The proposed system is composed of repeatable, independent modular pieces; each houses one column unit and two wall units that can be extruded or restructured depending on the designs of the user. Those components are driven by servo motors which translate into agile movements to instantly reflect any change of layout a designer draws in the software. The current machine design with a 4 x 4 module grid can create a completely enclosed 3 x 3-grid plan and is able to visualize simple plans layouts. With the increased number of modules in the machine, a higher number of combinatorial plan schematics can be represented and more complex architectural plans can be visualized. The analysis of plans suggest a finite 12 x 12 module grid on the machine, or a 11 x 11-grid plan, is sufficient in the context of visualization for commonly practiced residential designs of architecture.by Yu Linlin Huang.S.B
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