27,525 research outputs found
Exchange rate sensitivity of China’s bilateral trade flows
Traditional assessments of the impact of exchange rate depreciation or appreciation on trade have involved estimating the elasticity of trade volume to relative prices. Such studies relied heavily on aggregated trade data. More recent studies employ bilateral trade data and methodologies such as ECM and gravity models. This study uses a generalized gravity model with data panel analysis in assessing the impact of currency depreciation or appreciation on bilateral trade flows between China and its top trading partners. The empirical evidence suggests exchange rates (both real and nominal) do not exert a significant influence on the overall exports from China. Thus, a devaluation or revaluation of the yuan should be expected to have only limited impact on China’s trade balance. Moreover, previous studies provide limited evidence of a negative relation between exchange rate volatility and trade flows. Given the current revaluation expectations, we find China’s anticipated shift toward a more flexible exchange rate regime fails to address China’s trade surplus issues, and thus will merely lead to a revaluation of the nominal exchange rate and increased exchange rate volatility. It appears a major overhaul of the country’s heavily subsidized export regime must first occur for the exchange rate to assume a larger role in China’s international trade.exchange rate; trade; China; competition; gravity model; panel
Period halving of Persistent Currents in Mesoscopic Mobius ladders
We investigate the period halving of persistent currents(PCs) of
non-interacting electrons in isolated mesoscopic M\"{o}bius ladders without
disorder, pierced by Aharonov-Bhom flux. The mechanisms of the period halving
effect depend on the parity of the number of electrons as well as on the
interchain hopping. Although the data of PCs in mesoscopic systems are
sample-specific, some simple rules are found in the canonical ensemble average,
such as all the odd harmonics of the PCs disappear, and the signals of even
harmonics are non-negative. {PACS number(s): 73.23.Ra, 73.23.-b, 68.65.-k}Comment: 6 Pages with 3 EPS figure
Constraints on asymmetry of the proton in chiral effective theory
We compute the asymmetry in the proton in chiral effective theory,
using phenomenological constraints based upon existing data. Unlike previous
meson cloud model calculations, which accounted for kaon loop contributions
with on-shell intermediate states alone, this work includes off-shell terms and
contact interactions, which impact the shape of the difference. We
identify a valence-like component of which is balanced by a
-function contribution to at , so that the integrals
of and over the experimentally accessible region are not
equal. Using a regularization procedure that preserves chiral symmetry and
Lorentz invariance, we find that existing data limit the integrated value of
the second moment of the asymmetry to the range at a scale of GeV. This is too small to account for the NuTeV anomaly and of the wrong
sign to enhance it.Comment: 5 pages, 4 figure
Effect of nickel on the microstructure and mechanical property of die-cast Al–Mg–Si–Mn alloy
The effect of nickel on the microstructure and mechanical properties of a die-cast Al–Mg–Si–Mn alloy has been investigated. The results show that the presence of Ni in the alloy promotes the formation of Ni-rich intermetallics. These occur consistently during solidification in the die-cast Al–Mg–Si–Mn alloy across different levels of Ni content. The Ni-rich intermetallics exhibit dendritic morphology during the primary solidification and lamellar morphology during the eutectic solidification stage. Ni was found to be always associated with iron forming AlFeMnSiNi intermetallics, and no Al3Ni intermetallic was observed when Ni concentrations were up to 2.06 wt% in the alloy. Although with different morphologies, the Ni-rich intermetallics were identified as the same AlFeMnSiNi phase bearing a typical composition of Al[100–140](Fe,Mn)[2–7]SiNi[4–9]. With increasing Ni content, the spacing of the α-Al–Mg2Si eutectic phase was enlarged in the Al–Mg–Si–Mn alloy. The addition of Ni to the alloy resulted in a slight increase in the yield strength, but a significant decrease in the elongation. The ultimate tensile strength (UTS) increased slightly from 300 to 320 MPa when a small amount (e.g. 0.16 wt%) of Ni was added to the alloy, but further increase of the Ni content resulted in a decrease of the UTS.The Engineering and Physical Sciences Research Council (EPSRC), Technology Strategy Board (TSB) and Jaguar Land Rover (JLR) in the United Kingdom
Pt decorated amorphous RuIr alloys as high efficiency electrocatalyst for methanol oxidation
This study focuses primarily on improving the utilization and
activity of anodic catalysts for methanol electro-oxidation. The
Direct Methanol Fuel Cell (DMFC) anodic catalyst, a carbon
supported Pt decorated amorphous RuIr nanoparticles catalyst
(Pt@RuIr/C) was prepared by a two-step reduction method. The
structure of Pt@RuIr/C nanoparticles was confirmed by
Transmission Electron Microscopy (TEM) and X-ray Diffraction
(XRD). The Pt@RuIr electrocatalysts exhibited good uniformity in
distribution. Cyclic Voltammetry experiments showed that under
the same quality of noble-metal, the Pt@RuIr/C catalyst had higher
activity than the PtRuIr/C catalyst for methanol oxidation. It was
also shown that the as-prepared structure of the Pt decorated
amorphous RuIr alloys could obviously decrease the usage of
noble-metal and enhance its catalytic activity at the same time.Web of Scienc
Advances in genetic engineering for plants abiotic stress control
Agricultural productivity is highly influenced by abiotic stresses, known as the most harmful factor concerning the growth and productivity of crops worldwide. Furthermore, industrial crops are nowadays highly influenced by abiotic stress; these include extremes in temperature, drought, salinity, heavy metals and radiation. Typical studies were discussed by many researchers about the control of abiotic stress in plants by the expression, over-expression or switching off abiotic stress-related genes. Despite the rapid evolution of the research, some crops are still expected to decline by 15 to 32% in the next fifty years. Consequently, engineering genes that protect and maintain the function and structure of cellular components can enhance tolerance to stress. This review presents principal methods adapted in the control of plants abiotic stresses including recent advances in using transgenes for the improvement of abiotic stress tolerance in plants. Specified analysis of recent advances in abiotic stress control could describe trehalose as a better compound in the control of plant abiotic stresses. Therefore, studies of genes-related trehalose metabolism and associated patterns could not only provide an improved plant metabolism, phenotypes and texture, but in fact, the plants become highly resistant to abiotic stress.Key words: Abiotic stresses, crops, expression, over-expression, switching off, trehalose, genes-related
Doubly Penalized Buckley-James Method for Survival Data with High-Dimensional Covariates
Recent interest in cancer research focuses on predicting patients\u27 survival by investigating gene expression profiles based on microarray analysis. We propose a doubly penalized Buckley-James method for the semiparametric accelerated failure time model to relate high-dimensional genomic data to censored survival outcomes, which uses a mixture of L1-norm and L2-norm penalties. Similar to the elastic-net method for linear regression model with uncensored data, the proposed method performs automatic gene selection and parameter estimation, where highly correlated genes are able to be selected (or removed) together. The two-dimensional tuning parameter is determined by cross-validation and uniform design. The proposed method is evaluated by simulations and applied to the Michigan squamous cell lung carcinoma study
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