We consider theoretically the formation and stability of quasi-one-dimensional many-body excitons in GaAs quantum wire structures under external photoexcitation conditions by solving the dynamically screened Bethe-Salpeter equation for realistic Coulomb interaction. In agreement with several recent experimental findings the calculated excitonic peak shows weak carrier-density dependence up to (...

Tunnelling (one-particle) density of states in the vicinity of Fermi level of a two-dimensional electron gas subjected to an external parallel and zeroth magnetic field is calculated. It reveals a pseudo-gap recently observed in the experiments. The gap originates in spin polarization of 2DEG. Non-monotonic dependence of energy on a Landau level filling factor (density) was obtained. It implies...

Population cycles occur frequently in forest insects. Time-series analysis of fluctuations in one such insect, the southern pine beetle (Dendroctonus frontalis), suggests that beetle dynamics are dominated by an ecological process acting in a delayed density-dependent manner. The hypothesis that delayed density dependence in this insect results from its interaction with predators was tested wit...

The doping dependence of specific heat and magnetic susceptibility has been investigated for Li(x)ZrNCl superconductors derived from a band insulator. As the carrier concentration is decreased, the anisotropy of superconducting gap changes from highly anisotropic to almost isotropic. It was also found that, upon reducing carrier density, the superconducting coupling strength and the magnetic su...

this study took an epidemiological approach toward the problem of drug addiction in tehran. the subjects were 300 addicts chosen on the basis of stratified random selection out of the population of 3627 prisoners who were all proven addicts and sentenced to imprisonment by the court in the year 1370. a descriptive survey showed that drug addiction generally, and heroin addiction specifically, i...

Theoretical computation of the pressure dependence superconducting state parameters of binary Ca60Al40 is reported using model potential formalism. Explicit expressions have been derived for the volume dependence of the electron–phonon coupling strength λ and the Coulomb pseudopotential μ* considering the variation of Fermi momentum KF and Debye temperature ӨD with volume. Well known Ashcroft’s...

A model has been proposed to describe the potential barrier that appears during interaction of two compacted layers consisting hydrophilic oxide nanoparticles different sizes in each layer upon saturation this structure with adsorbed water. The dependence space charge density powder material on particles it theoretically calculated. distribution over thickness contact between obtained.

Glutathione S-transferases (GSTs; EC: 2.5.1.18) are ubiquitous multifunctional enzymes, which play a key role in cellular detoxification. Functional genetic polymorphisms in genes encoding GSTM1 (a member of GST class mu; OMIM: 138350), and GSTT1 (a member of GST class theta; OMIM: 600436) have been well defined. The functional null alleles of GSTM1 and GSTT1 represent deletions of GSTM1 and GS...