Influence of Long-term Cytotoxic Chemotherapy on the Condition of Peripheral Venous Channel

The necessity of long-term venous access in cancer patients appears at frequent and long-term courses of cytotoxic therapy. Peripheral veins of forearms are most often used for these aims. The conditions of peripheral venous channel in 32 cancer patients, who underwent the long-term treatment with antitumor preparations were analyzed in the article on own investigatory material.The methods of dopplerography, morphological and immunohystochemical studies were used. The qualitative and quantitative dopplerographic changes in forearm veins in different terms after chemotherapy start were revealed in most patients. The conclusion was made about unsuitability of forearm peripheral veins for the long term administration of cytostatics and the necessity to create the alternative vascular access that would correspond to the criteria of safety, reliability and long-term exploitation

Effect of the generalized uncertainty principle on Galilean and Lorentz transformations

Generalized Uncertainty Principle (GUP) was obtained in string theory and quantum gravity and suggested the existence of a fundamental minimal length which, as was established, can be obtained within the deformed Heisenberg algebra. We use the deformed commutation relations or in classical case (studied in this paper) the deformed Poisson brackets, which are invariant with respect to the translation in configurational space. We have found transformations relating coordinates and times of moving and rest frames of reference in the space with GUP in the first order over parameter of deformation. For the non-relativistic case we find the deformed Galilean transformation which is similar to the Lorentz one written for Euclidean space with signature $(+,+,+,+)$. The role of the speed of light here plays some velocity $u$ related to the parameter of deformation, which as we estimate is many order of magnitude larger than the speed of light $u\simeq 1.2 \times 10^{22} c$. The coordinates of the rest and moving frames of reference for relativistic particle in the space with GUP satisfy the Lorentz transformation with some effective speed of light. We estimate that the relative deviation of this effective speed of light $\tilde c$ from $c$ is ${(\tilde c-c)/ c}\simeq 3.5\times 10^{-45}$. The influence of GUP on the motion of particle and the Lorentz transformation in the first order over parameter of deformation is hidden in $1/c^2$ relativistic effects.Comment: 16 pages. arXiv admin note: text overlap with arXiv:1301.189

Anti-ferrodistortive Nanodomains in PMN Relaxor

Temperature dependent studies of the 1/2(hk0) superlattice reflections \alpha spots by synchrotron x-ray scattering measurements were performed in (PMN) and (PMN-xPT) with Ti doping x<0.32 single crystals. Separation of the \alpha spots from the underlying diffuse scattering background allowed studying them as separate entities for the first time. Structure factor calculations have shown that alpha spots constitute the presence of a new kind of anti-ferrodistortive nanoregions (AFR) in the form of fluctuations produced by anti-parallel short-range correlated Pb^2+ displacements. AFR appear to be different and unrelated to the chemical nanodomains (CND) and ferroelectric polar nanoregions (PNR). Simultaneous presence of AFR and PNR can explain relaxor behavior as a result of competition between randomly occurring ferroelectric and anti-ferroelectric fluctuations. Temperature dependence of the \alpha spots in PMN showed a direct correlation with the freezing phase transition near Tf~220 K.Comment: 10 pages, 7 figures, Conference-Fundamental Physics of Ferroelectrics 200

More on a SUSYQM approach to the harmonic oscillator with nonzero minimal uncertainties in position and/or momentum

We continue our previous application of supersymmetric quantum mechanical methods to eigenvalue problems in the context of some deformed canonical commutation relations leading to nonzero minimal uncertainties in position and/or momentum. Here we determine for the first time the spectrum and the eigenvectors of a one-dimensional harmonic oscillator in the presence of a uniform electric field in terms of the deforming parameters $\alpha$, $\beta$. We establish that whenever there is a nonzero minimal uncertainty in momentum, i.e., for $\alpha \ne 0$, the correction to the harmonic oscillator eigenvalues due to the electric field is level dependent. In the opposite case, i.e., for $\alpha = 0$, we recover the conventional quantum mechanical picture of an overall energy-spectrum shift even when there is a nonzero minimum uncertainty in position, i.e., for $\beta \ne 0$. Then we consider the problem of a $D$-dimensional harmonic oscillator in the case of isotropic nonzero minimal uncertainties in the position coordinates, depending on two parameters $\beta$, $\beta'$. We extend our methods to deal with the corresponding radial equation in the momentum representation and rederive in a simple way both the spectrum and the momentum radial wave functions previously found by solving the differential equation. This opens the way to solving new $D$-dimensional problems.Comment: 26 pages, no figure, new section 2.4 + small changes, accepted in J. Phys. A, Special issue on Supersymmetric Quantum Mechanic

Relation of deformed nonlinear algebras with linear ones

The relation between nonlinear algebras and linear ones is established. For one-dimensional nonlinear deformed Heisenberg algebra with two operators we find the function of deformation for which this nonlinear algebra can be transformed to a linear one with three operators. We also establish the relation between Lie algebra of total angular momentum and corresponding nonlinear one. This relation gives a possibility to simplify and to solve the eigenvalue problem for the Hamiltonian in a nonlinear case using the reduction of this problem to the case of linear algebra. It is demonstrated on the example of harmonic oscillator.Comment: 17 page

On the patterns of trade convergence in European transition countries

In current study we analyze the convergence of trade between Central and Eastern European countries (CEECs) and European Union (EU) during the period from 1984 to 2004. In our extension of the theoretical framework of Helpman, Melitz and Rubinstein (2005) with heterogeneous firms we discuss the influence of economic fundamentals and trade cost on extensive and intensive margins of trade. Then, we use gravity model of trade to calculate potentials for CEECs trade with EU-15 countries. As a result, we develop convergence measures for CEECs exports and imports trade flows with EU-15. Moreover, we provide decomposition of trade flows on extensive and intensive margins, and construct convergence measures for each of the trade components. Finally, we analyze the mechanics of trade convergence process in selected CEECs. Current paper contributes to better understanding of trade convergence patterns in European transition countries, providing policy-makers in transition economies with useful insights on the role of different trade components in the convergence process.trade convergence, gravity model, extensive and intensive margins, Hummels-Klenow decomposition

Lorentz-covariant deformed algebra with minimal length and application to the 1+1-dimensional Dirac oscillator

The $D$-dimensional $(\beta, \beta')$-two-parameter deformed algebra introduced by Kempf is generalized to a Lorentz-covariant algebra describing a ($D+1$)-dimensional quantized space-time. In the D=3 and $\beta=0$ case, the latter reproduces Snyder algebra. The deformed Poincar\'e transformations leaving the algebra invariant are identified. It is shown that there exists a nonzero minimal uncertainty in position (minimal length). The Dirac oscillator in a 1+1-dimensional space-time described by such an algebra is studied in the case where $\beta'=0$. Extending supersymmetric quantum mechanical and shape-invariance methods to energy-dependent Hamiltonians provides exact bound-state energies and wavefunctions. Physically acceptable states exist for $\beta < 1/(m^2 c^2)$. A new interesting outcome is that, in contrast with the conventional Dirac oscillator, the energy spectrum is bounded.Comment: 20 pages, no figure, some very small changes, published versio