7,009 research outputs found
PUBLIC INVESTMENT AND CHINA'S GRAIN PRODUCTION COMPETITIVENESS UNDER WTO
China's accession to the WTO poses great challenges to the Chinese agricultural sector, especially to the grain producers. Compared with major grain exporters in the world, most grain crops in China are high in production cost and weak in market competitiveness. This can be partly attributed to the fact that Chinese farmers are facing with poorer agricultural production infrastructures and inadequate public investment in agricultural research and extension, which leads to the lower efficiency in private inputs and thus higher private cost per unit of product. After China joining the WTO, protective and administrative measures conflicted with the URAA cannot be utilized as before. Alternative measures should be explored to provide help to farmers to improve competitiveness of their product. Public investment in agricultural research and other production infrastructures should be considered with high priority as one of the policy alternatives. This paper examines the effects of public investment in agricultural research on the reduction of production cost of major grain crops in China by using crop-specific data for the past 20 year. It is concluded that, increasing public investment in agricultural research, which is well within the "green box" policy framework and allowed by the WTO rules, is a plausible and effective measure to reduce grain producer's private input and to enhance the competitiveness of grain products. It is also of great significance to sustained food security in China.public investment, agricultural research, grain production, China, WTO, Crop Production/Industries, H540, Q170, Q180,
Slow light with a swept-frequency source
We introduce a new concept for stimulated-Brillouin-scattering-based slow
light in optical fibers that is applicable for broadly-tunable frequency-swept
sources. It allows slow light to be achieved, in principle, over the entire
transparency window of the optical fiber. We demonstrate a slow light delay of
10 ns at 1550 nm using a 10-m-long photonic crystal fiber with a source sweep
rate of 0.4 MHz/ns and a pump power of 200 mW. We also show that there exists a
maximal delay obtainable by this method, which is set by the SBS threshold,
independent of sweep rate. For our fiber with optimum length, this maximum
delay is ~38 ns, obtained for a pump power of 760 mW.Comment: 6 pages, 5 figure
Synthesis and structure of the inclusion complex {NdQ[5]K@Q[10](H₂O)4}·4NO₃·20H₂O
Heating a mixture of Nd(NO₃)₃·6H₂O, KCl, Q[10] and Q[5] in HCl for 10 min affords the inclusion complex {NdQ[5]K@Q[10](H₂O)₄}·4NO₃·20H₂O. The structure of the inclusion complex has been investigated by single crystal X-ray diffraction and by X-ray Photoelectron spectroscopy (XPS)
Erratum to: Gastrointestinal Dysfunction in a Parkinson’s Disease Rat Model and the Changes of Dopaminergic, Nitric Oxidergic, and Cholinergic Neurotransmitters in Myenteric Plexus
The distribution of ejected subhalos and its implication for halo assembly bias
Using a high-resolution cosmological -body simulation, we identify the
ejected population of subhalos, which are halos at redshift but were once
contained in more massive `host' halos at high redshifts. The fraction of the
ejected subhalos in the total halo population of the same mass ranges from 9%
to 4% for halo masses from to \sim 10^{12}\msun. Most of the
ejected subhalos are distributed within 4 times the virial radius of their
hosts. These ejected subhalos have distinct velocity distribution around their
hosts in comparison to normal halos. The number of subhalos ejected from a host
of given mass increases with the assembly redshift of the host. Ejected
subhalos in general reside in high-density regions, and have a much higher bias
parameter than normal halos of the same mass. They also have earlier assembly
times, so that they contribute to the assembly bias of dark matter halos seen
in cosmological simulations. However, the assembly bias is {\it not} dominated
by the ejected population, indicating that large-scale environmental effects on
normal halos are the main source for the assembly bias.Comment: revised version, submitted to MNRA
Electrically tunable resonant scattering in fluorinated bilayer graphene
Adatom-decorated graphene offers a promising new path towards spintronics in
the ultrathin limit. We combine experiment and theory to investigate the
electronic properties of dilutely fluorinated bilayer graphene, where the
fluorine adatoms covalently bond to the top graphene layer. We show that
fluorine adatoms give rise to resonant impurity states near the charge
neutrality point of the bilayer, leading to strong scattering of charge
carriers and hopping conduction inside a field-induced band gap. Remarkably,
the application of an electric field across the layers is shown to tune the
resonant scattering amplitude from fluorine adatoms by nearly twofold. The
experimental observations are well explained by a theoretical analysis
combining Boltzmann transport equations and fully quantum-mechanical methods.
This paradigm can be generalized to many bilayer graphene-adatom materials, and
we envision that the realization of electrically tunable resonance may be a key
advantage in graphene-based spintronic devices.We thank X. Hong for helpful discussions.
A.S., J.L., and J.Z. are supported by ONR
under Grant No. N00014-11-1-0730 and by NSF CAREER
Grant No. DMR-0748604. A.F. and N.M.R.P.
acknowledge EC under Graphene Flagship (Contract
No. CNECT-ICT-604391). A.F. gratefully acknowledges
the financial support of the Royal Society (U.K.) through
a Royal Society University Research Fellowship. We acknowledge
use of facilities at the PSU site of NSF NNIN
ALS Mutations of FUS Suppress Protein Translation and Disrupt the Regulation of Nonsense-Mediated Decay
Amyotrophic lateral sclerosis (ALS) is an incurable neurodegenerative disease characterized by preferential motor neuron death. Approximately 15% of ALS cases are familial, and mutations in the fused in sarcoma (FUS) gene contribute to a subset of familial ALS cases. FUS is a multifunctional protein participating in many RNA metabolism pathways. ALS-linked mutations cause a liquid–liquid phase separation of FUS protein in vitro, inducing the formation of cytoplasmic granules and inclusions. However, it remains elusive what other proteins are sequestered into the inclusions and how such a process leads to neuronal dysfunction and degeneration. In this study, we developed a protocol to isolate the dynamic mutant FUS-positive cytoplasmic granules. Proteomic identification of the protein composition and subsequent pathway analysis led us to hypothesize that mutant FUS can interfere with protein translation. We demonstrated that the ALS mutations in FUS indeed suppressed protein translation in N2a cells expressing mutant FUS and fibroblast cells derived from FUS ALS cases. In addition, the nonsense-mediated decay (NMD) pathway, which is closely related to protein translation, was altered by mutant FUS. Specifically, NMD-promoting factors UPF1 and UPF3b increased, whereas a negative NMD regulator, UPF3a, decreased, leading to the disruption of NMD autoregulation and the hyperactivation of NMD. Alterations in NMD factors and elevated activity were also observed in the fibroblast cells of FUS ALS cases. We conclude that mutant FUS suppresses protein biosynthesis and disrupts NMD regulation, both of which likely contribute to motor neuron death
Risk Perceptions of Cellphone Use While Driving: Results from a Delphi Survey
Cellphone use while driving has been recognized as a growing and important public health issue by the World Health Organization and U.S. Center for Disease Control and Prevention. Surveys typically collect data on overall texting while driving, but do not differentiate between various forms of cellphone use. This study sought to improve the survey indicators when monitoring cellphone use among young drivers. Experts and young drivers were recruited to propose behavioral indicators (cellphone use while driving behaviors) and consequential indicators (safety consequences of cellphone use while driving) in 2016. Subsequently, experts and young drivers selected the top indicators using the Delphi survey method. We enrolled 22 experts with published articles on cellphone use while driving nationally, and seven young drivers who were freshmen at a state university. Sending a text or e-mail on a handheld phone was picked as the top behavioral indicator by both groups. However, young drivers chose playing music on a handheld phone as the second most important behavioral indicator, which was overlooked by experts. Injury/death and collision were the top two consequential indicators. Experts and young drivers identified the important survey indicators to monitor cellphone use while driving
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