Magnetic Field Effect for Two Electrons in a Two Dimensional Random Potential

We study the problem of two particles with Coulomb repulsion in a two-dimensional disordered potential in the presence of a magnetic field. For the regime, when without interaction all states are well localized, it is shown that above a critical excitation energy electron pairs become delocalized by interaction. The transition between the localized and delocalized regimes goes in the same way as the metal-insulator transition at the mobility edge in the three dimensional Anderson model with broken time reversal symmetry.Comment: revtex, 7 pages, 6 figure

Ground state properties of the 2D disordered Hubbard model

We study the ground state of the two-dimensional (2D) disordered Hubbard model by means of the projector quantum Monte Carlo (PQMC) method. This approach allows us to investigate the ground state properties of this model for lattice sizes up to $10 \times 10$, at quarter filling, for a broad range of interaction and disorder strengths. Our results show that the ground state of this system of spin-1/2 fermions remains localised in the presence of the short-ranged Hubbard interaction.Comment: 7 pages, 9 figure

Correlation energy of a two-dimensional electron gas from static and dynamic exchange-correlation kernels

We calculate the correlation energy of a two-dimensional homogeneous electron gas using several available approximations for the exchange-correlation kernel $f_{\rm xc}(q,\omega)$ entering the linear dielectric response of the system. As in the previous work of Lein {\it et al.} [Phys. Rev. B {\bf 67}, 13431 (2000)] on the three-dimensional electron gas, we give attention to the relative roles of the wave number and frequency dependence of the kernel and analyze the correlation energy in terms of contributions from the $(q, i\omega)$ plane. We find that consistency of the kernel with the electron-pair distribution function is important and in this case the nonlocality of the kernel in time is of minor importance, as far as the correlation energy is concerned. We also show that, and explain why, the popular Adiabatic Local Density Approximation performs much better in the two-dimensional case than in the three-dimensional one.Comment: 9 Pages, 4 Figure

Urodynamics and laser prostatectomy

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Urodynamics and laser prostatectomy

A total of 81 patients with symptomatic bladder-outlet obstruction (BOO) due to benign prostatic hyperplasia (BPH) underwent visual laser ablation of the prostate (VLAP) using a right-angled firing neodynium: YAG laser. The mean pre-operative prostatic volume was 48.5 ml. All patients were discharged on the 1st post-operative day with an indwelling catheter. Two patients underwent a transurethral prostatectomy (TURP) after failing a trial without catheter on two occasions. Of the remaining 79 patients, 75 were evaluated 6 months post-operatively. Mean symptom scores (I-PSS) decreased from 20.9 to 5.8, the mean maximal urinary flow rate increased from 7.9 to 16.4 ml/s and the mean residual volume decreased from 88.1 to 15.6 ml. Several different methods of evaluating BOO from pressure-flow measurements were used and all showed improvement. All the above-mentioned parameters showed a highly significant improvement (P <0.01) at 6 month