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, $\Phi$-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 $c$-axis resistivity, $\rho_c$, for \lsco, \ybco and \bsco . We argue that the $c$-axis resistivity can be separated into contributions from in-plane dephasing and the $c$-axis ``barrier'' scattering processes, with the low temperature semiconductor-like behavior of $\rho_c$ arising from the suppression of the in-plane density of states measured by in-plane magnetic Knight shift experiments. We report on predictions for $\rho_c$ in impurity-doped \ybco materials.Comment: 10 pages + figures, also see March Meeting J13.1

Coherent `ab' and `c' transport theory of high-TcT_{c} cuprates

We propose a microscopic theory of the `$c$'-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, $\rho_{c}(T,x)/\rho_{ab}(T,x)\sim x/\sqrt{T}\chi_{s}(T,x)$. The temperature $(T)$ and doping $(x)$ dependence of the in-plane, $\rho_{ab}$ and out-of-plane, $\rho_{c}$ resistivity and the spin susceptibility, $\chi_{s}$ are found in a remarkable agreement with the experimental data in underdoped, optimally and overdoped $La_{2-x}Sr_{x}CuO_{4}$ for the entire temperature regime from $T_{c}$ up to $800K$. 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$_c$ 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 $^{63}T_1$ and the magnetic scaling behavior proposed by Barzykin and Pines. The reconciliation of the $^{17}T_1$ 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 $C'$ between oxygen nuclei and their next nearest neighbor $Cu^{2+}$ 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 $C'$ 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 $et~al$. The measured significant decrease with doping of the anisotropy ratio, $R= ^{63}T_{1ab}/^{63}T_{1c}$ in LSCO system, from $R =3.9$ for ${\rm La_2CuO_4}$ to $R ~ 3.0$ 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 $A_{\beta}$ and B.Comment: 24 pages in RevTex, 9 figures include