Intermixture of extended edge and localized bulk energy levels in macroscopic Hall systems

We study the spectrum of a random Schroedinger operator for an electron submitted to a magnetic field in a finite but macroscopic two dimensional system of linear dimensions equal to L. The y direction is periodic and in the x direction the electron is confined by two smooth increasing boundary potentials. The eigenvalues of the Hamiltonian are classified according to their associated quantum mechanical current in the y direction. Here we look at an interval of energies inside the first Landau band of the random operator for the infinite plane. In this energy interval, with large probability, there exist O(L) eigenvalues with positive or negative currents of O(1). Between each of these there exist O(L^2) eigenvalues with infinitesimal current O(exp(-cB(log L)^2)). We explain what is the relevance of this analysis to the integer quantum Hall effect.Comment: 29 pages, no figure

Matrix Models, Argyres-Douglas singularities and double scaling limits

We construct an N=1 theory with gauge group U(nN) and degree n+1 tree level superpotential whose matrix model spectral curve develops an A_{n+1} Argyres-Douglas singularity. We evaluate the coupling constants of the low-energy U(1)^n theory and show that the large N expansion is singular at the Argyres-Douglas points. Nevertheless, it is possible to define appropriate double scaling limits which are conjectured to yield four dimensional non-critical string theories as proposed by Ferrari. In the Argyres-Douglas limit the n-cut spectral curve degenerates into a solution with n/2 cuts for even n and (n+1)/2 cuts for odd n.Comment: 31 pages, 1 figure; the expression of the superpotential has been corrected and the calculation of the coupling constants of the low-energy theory has been adde

Effect of ELF e.m. fields on metalloprotein redox-active sites

The peculiarity of the distribution and geometry of metallic ions in enzymes pushed us to set the hypothesis that metallic ions in active-site act like tiny antennas able to pick up very feeble e.m. signals. Enzymatic activity of Cu2+, Zn2+ Superoxide Dismutase (SOD1) and Fe2+ Xanthine Oxidase (XO) has been studied, following in vitro generation and removal of free radicals. We observed that Superoxide radicals generation by XO is increased by a weak field having the Larmor frequency fL of Fe2+ while the SOD1 kinetics is sensibly reduced by exposure to a weak field having the frequency fL of Cu2+ ion.Comment: 18 pages, 4 figure

Effect of diuretics on the plasma lipid profile

Hypertension, dyslipidaemia, glucose intolerance (associated with insulin resistance and compensatory hyperinsulinaemia) and other abnormalities are complementary coronary risk factors which often occur in association. A familial trait for essential hypertension seems to coexist commonly with defects in carbohydrate and lipoprotein metabolism which can be detected before the appearance of hypertension. Diabetes mellitus as well as obesity promotes the development of hypertension and dyslipidaemia. Moreover, certain drugs used for antihypertensive therapy can further modify lipoprotein and glucose metabolism. Thiazides in high dosage and loop-diuretics can increase serum low-density-lipoprotein cholesterol (LDL-C) and/or verv-LDL-C and the total C/high-density lipoprotein cholesterol (HDL-C) ratio, while HDL-C is largely unchanged; triglycerides (Tg) are also often elevated. Premenopausal women may beprotected from this side effect. Whether diureticinduced dyslipidaemia is dose-dependent and low thiazide doses (i.e. hydrochlorothiazide ≤12·5 mg daily) are less active, awaits clarification. The diuretic-antihypertensive agent, indapamide, given at a dose of 2·5 mg. day−1, seems to exert no relevant effect on serum lipoprotein or glucose metabolism. The potassium-sparing diuretic, spironolactone, also may be largely neutral with regard to lipids. Moreover, potassium sparing diuretics may possibly counteract, at least in part, a dyslipidaemic influence of potassium-loosing diuretics in medium dose. Drug-induced dyslipidaemia, as well as glucose intolerance, represent potentially adverse influences. In the hypertensive population, effective blood pressure control with traditional drug therapy based on thiazide-type diuretics in high dosage led to a distinct decrease in cerebrovascular morbidity and mortality, but a lesser decrease in coronary events. The prognostic relevance of drug-induced metabolic changes such as dyslipidaemia, altered insulin sensitivity, and glucose intolerance awaits further clarification. It is of clinical interest that several of the generally available antihypertensive drugs seem to be metabolically ‘neutral' or sometimes perhaps even potentially beneficial with regard to the lipoprotein and glucose metabolis

Uso do lodo de esgoto para recuperação de áreas degradadas.

O uso do lodo de esgoto para fins agrícolas e florestais, ultimamente está tendo uma forte demanda, pois além de fornecer elementos químicos importantes para as plantas, este também condiciona as propriedades físicas do solo, devido a grande quantidade de matéria orgânica nele presente. Além do uso do lodo de esgoto para fins agrícolas e florestais, em plantios comerciais, outra alternativa é recuperar solo degradado que sofreu alterações físicas e/ou químicas. Este trabalho teve como objetivo avaliar o uso do lodo de esgoto em plantações e na recuperação de áreas degradadas, por meio de parâmetros de físicos e químicos do solo. Nas avaliações feitas antes e depois da instalação do experimento, nota-se uma variação na macro e micro porosidade e também na retenção de água no perfil de solo que mostrou aumento. Houve o desenvolvimento de gramíneas, o que ajuda na melhoria da porosidade e da distribuição de tamanho de poros. Em cada parcela foram feitas 4 trincheiras até a profundidade de 40 cm. Nos resultados finais houve uma variação na macroporosidade de 18,9% no primeiro ano para 25,3% no segundo, na microporosidade a variação foi de 33,1% no primeiro ano para 27,3% no segundo; na densidade 1,3 kg/dm3 no primeiro ano e 1,2 kg/dm3 no segundo; no tratamento 100T de Lodo. Os dados se referem a uma caracterização inicial do experimento, e 1 ano após a instalação

Vagus nerve stimulation: A new approach to reduce heart failure

Autonomic imbalance with increased adrenergic and reduced parasympathetic activity is involved in the development and progress of heart failure (HF). Experimental data have demonstrated that stimulation of the vagus nerve is able to reverse ventricular remodeling of the failing heart. There is also evidence that increasing parasympathetic activity may stimulate the production of nitric oxide, and reduce the devastating inflammatory process involved in HF. Vagus nerve stimulation (VNS) has been successfully applied for many years to treat drug resistant epilepsy. The first study of right vagus stimulation in patients with advance HF has proven the feasibility and safety of this new approach. Long term follow-up of increased vagal tone over 12 months with a specially designed stimulating system (CardioFit, BioControl, Yehud, Israel) has demonstrated that symptoms of HF can be significantly diminished, left ventricular ejection fraction increased, and ventricular volumes reduced. These recently published data are very promising and may offer another approach for patients with advanced HF already treated with optimal medical therapy. A prospective randomized trial with a larger patient cohort is needed to confirm these beneficial results of VNS. (Cardiol J 2010; 17, 6: 638-643