2,200 research outputs found
The effect of tax structure in economic growth
The main goal of this paper is to analyse the effect of the tax structure in the economic growth of Kosovo in the period 2007-2015. The study intends to evaluate the impact of specific types of taxes on economic growth.
The methodology is based on comparative analysis of data using primary and secondary sources. Through the econometric model and linear regression analysis, the research hypotheses have been tested with STATA application/software to calculate the impact of tax structure in economic growth.
The econometric model includes several independent variables (types of taxes), and the dependent variable GDP. Based on data obtained through the log-log model, the results show the impact of special taxes such as Pt, It, VAT, Wt, Ibt, Tdr.., Ct on GDP.
The results show that most of the taxes have a positive impact on GDP growth; it is also shown that not all taxes have the same impact on economic growth.
In the econometric analysis the coefficient of R2=0,999 reflects the high degree of determination with 99.9% forecasting accuracy.peer-reviewe
Space efficient opposed-anvil high-pressure cell and its application to optical and NMR measurements up to 9 GPa
We have developed a new type of opposed-anvil high pressure cell with
substantially improved space efficiency. The clamp cell and the gasket are made
of non-magnetic Ni-Cr-Al alloy. Non-magnetic tungsten carbide (NMWC) is used
for the anvils. The assembled cell with the dimension \phi 29mm \times 41mm is
capable of generating pressure up to 9 GPa over a relatively large volume of 7
mm3. Our cell is particularly suitable for those experiments which require
large sample space to achieve good signal-to-noise ratio, such as the nuclear
magnetic resonance (NMR) experiment. Argon is used as the pressure transmitting
medium to obtain good hydrostaticity. The pressure was calibrated in situ by
measuring the fluorescence from ruby through a transparent moissanite (6H-SiC)
window. We have measured the pressure and temperature dependences of the 63Cu
nuclear-quadrupole-resonance (NQR) frequency of Cu2O, the in-plane Knight shift
of metallic tin, and the Knight shift of platinum. These quantities can be used
as reliable manometers to determine the pressure values in situ during the
NMR/NQR experiments up to 9 GPa.Comment: 9 pages, 5 figures, 3 tables, accepted for publication in J. Phys.
Soc. Jp
The Dynamical Cluster Approximation: Non-Local Dynamics of Correlated Electron Systems
We recently introduced the dynamical cluster approximation(DCA), a new
technique that includes short-ranged dynamical correlations in addition to the
local dynamics of the dynamical mean field approximation while preserving
causality. The technique is based on an iterative self-consistency scheme on a
finite size periodic cluster. The dynamical mean field approximation (exact
result) is obtained by taking the cluster to a single site (the thermodynamic
limit). Here, we provide details of our method, explicitly show that it is
causal, systematic, -derivable, and that it becomes conserving as the
cluster size increases. We demonstrate the DCA by applying it to a Quantum
Monte Carlo and Exact Enumeration study of the two-dimensional Falicov-Kimball
model. The resulting spectral functions preserve causality, and the spectra and
the CDW transition temperature converge quickly and systematically to the
thermodynamic limit as the cluster size increases.Comment: 19 pages, 13 postscript figures, revte
Model of C-Axis Resistivity of High-\Tc Cuprates
We propose a simple model which accounts for the major features and
systematics of experiments on the -axis resistivity, , for \lsco,
\ybco and \bsco . We argue that the -axis resistivity can be separated
into contributions from in-plane dephasing and the -axis ``barrier''
scattering processes, with the low temperature semiconductor-like behavior of
arising from the suppression of the in-plane density of states
measured by in-plane magnetic Knight shift experiments. We report on
predictions for in impurity-doped \ybco materials.Comment: 10 pages + figures, also see March Meeting J13.1
Coherent `ab' and `c' transport theory of high- cuprates
We propose a microscopic theory of the `'-axis and in-plane transport of
copper oxides based on the bipolaron theory and the Boltzmann kinetics. The
fundamental relationship between the anisotropy and the spin susceptibility is
derived, . The
temperature and doping dependence of the in-plane, and
out-of-plane, resistivity and the spin susceptibility,
are found in a remarkable agreement with the experimental data in underdoped,
optimally and overdoped for the entire temperature
regime from up to . The normal state gap is explained and its
doping and temperature dependence is clarified.Comment: 12 pages, Latex, 3 figures available upon reques
C-axis resistivity and high Tc superconductivity
Recently we had proposed a mechanism for the normal-state C-axis resistivity
of the high-T layered cuprates that involved blocking of the
single-particle tunneling between the weakly coupled planes by strong
intra-planar electron-electron scattering. This gave a C-axis resistivity that
tracks the ab-plane T-linear resistivity, as observed in the high-temperature
limit. In this work this mechanism is examined further for its implication for
the ground-state energy and superconductivity of the layered cuprates. It is
now argued that, unlike the single-particle tunneling, the tunneling of a
boson-like pair between the planes prepared in the BCS-type coherent trial
state remains unblocked inasmuch as the latter is by construction an eigenstate
of the pair annihilation operator. The resulting pair-delocalization along the
C-axis offers energetically a comparative advantage to the paired-up trial
state, and, thus stabilizes superconductivity. In this scheme the strongly
correlated nature of the layered system enters only through the blocking
effect, namely that a given electron is effectively repeatedly monitored
(intra-planarly scattered) by the other electrons acting as an environment, on
a time-scale shorter than the inter-planar tunneling time. Possible
relationship to other inter-layer pairing mechanisms proposed by several
workers in the field is also briefly discussed.Comment: typos in equations corrected, contents unchange
Pi excitation of the t-J model
In this paper, we present analytical and numerical calculations of the pi
resonance in the t-J model. We show in detail how the pi resonance in the
particle-particle channel couples to and appears in the dynamical spin
correlation function in a superconducting state. The contribution of the pi
resonance to the spin excitation spectrum can be estimated from general
model-independent sum rules, and it agrees with our detailed calculations. The
results are in overall agreement with the exact diagonalization studies of the
t-J model. Earlier calculations predicted the correct doping dependence of the
neutron resonance peak in the YBCO superconductor, and in this paper detailed
energy and momentum dependence of the spin correlation function is presented.
The microscopic equations of motion obtained within current formalism agree
with that of the SO(5) nonlinear sigma model, where the pi resonance is
interpreted as a pseudo Goldstone mode of the spontaneous SO(5) symmetry
breaking.Comment: 33 pages, LATEX, 14 eps fig
Effect of Nonmagnetic Impurities on the Magnetic Resonance Peak in YBa2Cu3O7
The magnetic excitation spectrum of a YBa_2 Cu_3 O_7 crystal containing 0.5%
of nonmagnetic (Zn) impurities has been determined by inelastic neutron
scattering. Whereas in the pure system a sharp resonance peak at E ~ 40 meV is
observed exclusively below the superconducting transition temperature T_c, the
magnetic response in the Zn-substituted system is broadened significantly and
vanishes at a temperature much higher than T_c. The energy-integrated spectral
weight observed near q = (pi,pi) increases with Zn substitution, and only about
half of the spectral weight is removed at T_c
Securitization in Chinese climate and energy politics
This article provides an overview of securitization in Chinese climate and energy debates. Scholars have debated the merits as well as the potentially problematic implications of securitization, or framing issues as ‘security,’ since the early 1990s. Early concern focused on the potential problems with linking environmental issues with ‘security,’ and the debate has since also turned specifically to the climate and energy. However, it is only recently that this debate has begun to pay attention to China. Energy and climate concerns are of increasing importance to China: the sheer scale of its energy consumption and air pollution struggles dwarf the challenges seen by other states, and its policy choices play a key role in shaping global climate and energy dynamics. Thus, while securitization in the Chinese context is rarely studied, how China frames its energy and climate policy matters. Both energy and climate are taken increasingly seriously, and security plays an increasing role in debates. This review surveys the increasing popularity of linking security with climate and energy issues both in the academic debate on China and in official discourse, and some of the potential implications
NMR and Neutron Scattering Experiments on the Cuprate Superconductors: A Critical Re-Examination
We show that it is possible to reconcile NMR and neutron scattering
experiments on both LSCO and YBCO, by making use of the Millis-Monien-Pines
mean field phenomenological expression for the dynamic spin-spin response
function, and reexamining the standard Shastry-Mila-Rice hyperfine Hamiltonian
for NMR experiments. The recent neutron scattering results of Aeppli et al on
LSCO (x=14%) are shown to agree quantitatively with the NMR measurements of
and the magnetic scaling behavior proposed by Barzykin and Pines.
The reconciliation of the relaxation rates with the degree of
incommensuration in the spin fluctuation spectrum seen in neutron experiments
is achieved by introducing a new transferred hyperfine coupling between
oxygen nuclei and their next nearest neighbor spins; this leads to a
near-perfect cancellation of the influence of the incommensurate spin
fluctuation peaks on the oxygen relaxation rates of LSCO. The inclusion of the
new term also leads to a natural explanation, within the one-component
model, the different temperature dependence of the anisotropic oxygen
relaxation rates for different field orientations, recently observed by
Martindale . The measured significant decrease with doping of the
anisotropy ratio, in LSCO system, from
for to for LSCO (x=15%) is made compatible with the
doping dependence of the shift in the incommensurate spin fluctuation peaks
measured in neutron experiments, by suitable choices of the direct and
transferred hyperfine coupling constants and B.Comment: 24 pages in RevTex, 9 figures include
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