23,731 research outputs found
The development of local government financial vehicles in China: A case study of Jiaxing Chengtou
Financial intermediaries have been widely used in urban development. Since the global financial crisis, it has been an urgent task to understand their operation and implications for financial risks. This paper examines emerging local government financial vehicles (LGFVs) in China. We review their history, current status and underlying financial mechanisms. Confronting the global financial crisis, China has taken a stimulus plan to invest four-trillion Yuan in urban development to stimulate the economy. The plan has been largely fulfilled by the LGFVs. This paper investigates the case of Jiaxing City Construction Investment Corporation (Jiaxing Chengtou), which plays a role of LGFVs. We find that it mainly uses bank loans and bonds to finance land and infrastructure development. To borrow from the capital market, Jiaxing Chengtou collateralizes allocated state-owned land and enhances credits by build and transfer protocols with the city government. However, the enterprise did not manage to pay back its loans, which has led to further borrowing. Due to the central government’s control, Jiaxing Chengtou has been nominally detached from the municipal government since 2012, but it maintains a financial role. It has been re-packaged with other LGFVs to access foreign bond markets. The paper reveals how LGFVs act as financial conduits to connect local governments with the financial market in China
Charmless decays B->pipi, piK and KK in broken SU(3)symmetry
Charmless B decay modes and aresystematically
investigated with and without flavor SU(3) symmetry. Independent analyses on
and modes both favor a large ratio between color-suppressed
tree () and tree ( diagram, which suggests that they are more likely to
originate from long distance effects. The sizes of QCD penguin diagrams
extracted individually from , and modes are found to
follow a pattern of SU(3) breaking in agreement with the naive factorization
estimates. Global fits to these modes are done under various scenarios of
SU(3)relations. The results show good determinations of weak phase in
consistency with the Standard Model (SM), but a large electro-weak penguin
(P_{\tmop{EW}}) relative to with a large relative strong phase are
favored, which requires an big enhancement of color suppressed electro-weak
penguin (P_{\tmop{EW}}^C) compatible in size but destructively interfering
with P_{\tmop{EW}} within the SM, or implies new physics. Possibility of
sizable contributions from nonfactorizable diagrams such as -exchange (),
annihilation() and penguin-annihilation diagrams() are investigated.
The implications to the branching ratios and CP violations in modes are
discussed.Comment: 27 pages, 9 figures, reference added, to appear in Phy.Rev.
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Experimental and Numerical Investigation on Progressive Collapse Resistance of Post-tensioned Precast Concrete Beam-Column Sub-assemblages
In this paper, four 1/2 scaled precast concrete (PC) beam-column sub-assemblages with high performance connection were tested under push-down loading procedure to study the load resisting mechanism of PC frames subjected to different column removal scenarios. The parameters investigated include the location of column removal and effective prestress in tendons. The test results indicated that the failure modes of unbonded post-tensioned precast concrete (PTPC) frames were different from that of reinforced concrete (RC) frames: no cracks formed in the beams and wide opening formed near the beam to column interfaces. For specimens without overhanging beams, the failure of side column was eccentric compression failure. Moreover, the load resisting mechanisms in PC frames were significantly different from that of RC frames: the compressive arch action (CAA) developed in concrete during column removal was mainly due to actively applied pre-compressive stress in the concrete; CAA will not vanish when severe crush in concrete occurred. Thus, it may provide negative contribution for load resistance when the displacement exceeds one-beam depth; the tensile force developed in the tendons could provide catenary action from the beginning of the test. Moreover, to deeper understand the behavior of tested specimens, numerical analyses were carried out. The effects of concrete strength, axial compression ratio at side columns, and loading approaches on the behavior of the sub-assemblages were also investigated based on validated numerical analysis
TeV Scale Lee-Wick Fields out of Large Extra Dimensional Gravity
We study the gravitational corrections to the Maxwell, Dirac and Klein-Gorden
theories in the large extra dimension model in which the gravitons propagate in
the (4+n)-dimensional bulk, while the gauge and matter fields are confined to
the four-dimensional world. The corrections to the two-point Green's functions
of the gauge and matter fields from the exchanges of virtual Kaluza-Klein
gravitons are calculated in the gauge independent background field method. In
the framework of effective field theory, we show that the modified one-loop
renormalizable Lagrangian due to quantum gravitational effects contains a TeV
scale Lee-Wick partner of every gauge and matter field as extra degrees of
freedom in the theory. Thus the large extra dimension model of gravity provides
a natural mechanism to the emergence of these exotic particles which were
recently used to construct an extension of the Standard Model.Comment: 17 pages, 3 figures, references added, to appear in Phys. Rev.
Seasonal and spatial variations of heavy metalsin surface sediments collected from the BaoxiangRiver in the Dianchi Watershed, China
To explore potential ecological hazards due to heavy metals in the
Dianchi Lake Watershed, a three-stage European Community Bureau of
Reference (BCR) sequential extraction procedure was applied to examine
the spatial distributions and relative speciation ratios of Zn, Cu, Ni, Pb,
and Cr in Baoxiang River sediments during wet and dry seasons. The
metal species have similar spatial variations during different seasons. In
the upstream reaches of the Baoxiang River, heavy metals reside
primarily in the non-extractable residual fraction (72–90%). In the
midstream, the residual fraction (35–89%) remains dominant, but the
extractable fraction increases, featuring especially notable increases in
the reducible fraction (5–40%). Downstream, the Cu, Ni, Pb, and Cr
residual fractions remain high (46–80%) and the extractable fractions
increase rapidly; the Zn extractable fraction is quite high (65.5%).
Anthropogenic sources drive changes in heavy metal speciation.
Changes in the river environment, such as pH and oxidation-reduction
potential, also affect speciation. The reducible fraction of heavy metals
in Baoxiang River sediments is most sensitive to pH. Potential ecological
risk assessments for these five elements indicate that risks from Zn and
Pb are mild to moderate in the middle and lower reaches of the river.<br style="line-height: normal; text-align: -webkit-auto; text-size-adjust: auto;" /
A Language and Hardware Independent Approach to Quantum-Classical Computing
Heterogeneous high-performance computing (HPC) systems offer novel
architectures which accelerate specific workloads through judicious use of
specialized coprocessors. A promising architectural approach for future
scientific computations is provided by heterogeneous HPC systems integrating
quantum processing units (QPUs). To this end, we present XACC (eXtreme-scale
ACCelerator) --- a programming model and software framework that enables
quantum acceleration within standard or HPC software workflows. XACC follows a
coprocessor machine model that is independent of the underlying quantum
computing hardware, thereby enabling quantum programs to be defined and
executed on a variety of QPUs types through a unified application programming
interface. Moreover, XACC defines a polymorphic low-level intermediate
representation, and an extensible compiler frontend that enables language
independent quantum programming, thus promoting integration and
interoperability across the quantum programming landscape. In this work we
define the software architecture enabling our hardware and language independent
approach, and demonstrate its usefulness across a range of quantum computing
models through illustrative examples involving the compilation and execution of
gate and annealing-based quantum programs
Superstructure-induced splitting of Dirac cones in silicene
Atomic scale engineering of two-dimensional materials could create devices
with rich physical and chemical properties. External periodic potentials can
enable the manipulation of the electronic band structures of materials. A
prototypical system is 3x3-silicene/Ag(111), which has substrate-induced
periodic modulations. Recent angle-resolved photoemission spectroscopy
measurements revealed six Dirac cone pairs at the Brillouin zone boundary of
Ag(111), but their origin remains unclear [Proc. Natl. Acad. Sci. USA 113,
14656 (2016)]. We used linear dichroism angle-resolved photoemission
spectroscopy, the tight-binding model, and first-principles calculations to
reveal that these Dirac cones mainly derive from the original cones at the K
(K') points of free-standing silicene. The Dirac cones of free-standing
silicene are split by external periodic potentials that originate from the
substrate-overlayer interaction. Our results not only confirm the origin of the
Dirac cones in the 3x3-silicene/Ag(111) system, but also provide a powerful
route to manipulate the electronic structures of two-dimensional materials.Comment: 6 pages, 3 figure
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