The possibilities and dangers in using malachite green in pisciculture.[Translation from: Informatsionnyi Byulleten Biologiya Vnutrennikh Vod No.3 17-21, 1969.]

For many years a dye has been used in the practise of pisciculture and pond management, which is known by the name of malachite green, and is used to combat fungus on fish, fish eggs and external animal parasites on fish. The authors describe the problem of the application of malachite green in pisciculture and undertake special, complementary research

Characterization of weakly ionized argon flows for radio blackout mitigation experiments

For reproducing the so-called E × B communication blackout mitigation scheme inside the L2K arc heated facility of the DLR in weakly ionized argon §ows, a §at plate model has been equipped with a superconducting magnet, electrodes, and a setup comprising microwave plasma transmission spectroscopy (MPTS). A thorough characterization of the weakly ionized argon §ow has been performed including the use of microwave interferometry (MWI), Langmuir probe measurements, Pitot probe pro¦les, and spectroscopic methods like diode laser absorption spectroscopy (DLAS) and emission spectroscopy

Exchange-correlation energy densities for two-dimensional systems from quantum dot ground-states

In this paper we present a new approach how to extract polarization-dependent exchange-correlation energy densities for two-dimensional systems from reference densities and energies of quantum dots provided by exact diagonalization. Compared with results from literature we find systematic corrections for all polarizations in the regime of high densities.Comment: 7 figures. submitted to Phys. Rev.

Role of PII proteins in nitrogen fixation control of Herbaspirillum seropedicae strain SmR1

<p>Abstract</p> <p>Background</p> <p>The PII protein family comprises homotrimeric proteins which act as transducers of the cellular nitrogen and carbon status in prokaryotes and plants. In <it>Herbaspirillum seropedicae</it>, two PII-like proteins (GlnB and GlnK), encoded by the genes <it>glnB </it>and <it>glnK</it>, were identified. The <it>glnB </it>gene is monocistronic and its expression is constitutive, while <it>glnK </it>is located in the <it>nlmAglnKamtB </it>operon and is expressed under nitrogen-limiting conditions.</p> <p>Results</p> <p>In order to determine the involvement of the <it>H. seropedicae glnB </it>and <it>glnK </it>gene products in nitrogen fixation, a series of mutant strains were constructed and characterized. The <it>glnK^-</it>mutants were deficient in nitrogen fixation and they were complemented by plasmids expressing the GlnK protein or an N-truncated form of NifA. The nitrogenase post-translational control by ammonium was studied and the results showed that the <it>glnK </it>mutant is partially defective in nitrogenase inactivation upon addition of ammonium while the <it>glnB </it>mutant has a wild-type phenotype.</p> <p>Conclusions</p> <p>Our results indicate that GlnK is mainly responsible for NifA activity regulation and ammonium-dependent post-translational regulation of nitrogenase in <it>H. seropedicae</it>.</p

Quantum-dot lithium in zero magnetic field: Electronic properties, thermodynamics, and a liquid-solid transition in the ground state

Energy spectra, electron densities, pair correlation functions and heat capacity of a quantum-dot lithium in zero external magnetic field (a system of three interacting two-dimensional electrons in a parabolic confinement potential) are studied using the exact diagonalization approach. A particular attention is given to a Fermi-liquid -- Wigner-solid transition in the ground state of the dot, induced by the intra-dot Coulomb interaction.Comment: 12 pages, incl. 16 figure

Exchange-correlation vector potentials and vorticity-dependent exchange-correlation energy densities in two-dimensional systems

We present a new approach how to calculate the scalar exchange-correlation potentials and the vector exchange-correlation potentials from current-carrying ground states of two-dimensional quantum dots. From these exchange-correlation potentials we derive exchange-correlation energy densities and examine their vorticity (or current) dependence. Compared with parameterizations of current-induced effects in literature we find an increased significance of corrections due to paramagnetic current densities.Comment: 5 figures, submitted to PR

Diffusion Monte Carlo study of circular quantum dots

We present ground and excited state energies obtained from Diffusion Monte Carlo (DMC) calculations, using accurate multiconfiguration wave functions, for $N$ electrons ($N\le13$) confined to a circular quantum dot. We analyze the electron-electron pair correlation functions and compare the density and correlation energies to the predictions of local spin density approximation theory (LSDA). The DMC estimated change in electrochemical potential as function of the number of electrons in the dot is compared to that from LSDA and Hartree-Fock (HF) calculations.Comment: 7 pages, 4 eps figures. To be published in Phys. Rev. B, September 15th 2000. See erratum cond-mat/030571

Current-spin-density functional study of persistent currents in quantum rings

We present a numerical study of persistent currents in quantum rings using current spin density functional theory (CSDFT). This formalism allows for a systematic study of the joint effects of both spin, interactions and impurities for realistic systems. It is illustrated that CSDFT is suitable for describing the physical effects related to Aharonov-Bohm phases by comparing energy spectra of impurity-free rings to existing exact diagonalization and experimental results. Further, we examine the effects of a symmetry-breaking impurity potential on the density and current characteristics of the system and propose that narrowing the confining potential at fixed impurity potential will suppress the persistent current in a characteristic way.Comment: 7 pages REVTeX, including 8 postscript figure

Pseudoscalar-pole contributions to the muon g−2g-2 at the physical point

Pseudoscalar-pole diagrams are an important component of estimates of the hadronic light-by-light (HLbL) contribution to the muon g−2. We report on our computation of the transition form factors P→γ∗γ∗ for the neutral pseudoscalar mesons P=π0 and η . The calculation is performed using twisted-mass lattice QCD with physical quark masses. On the lattice, we have access to a broad range of (space-like) photon four-momenta and therefore produce form factor data complementary to the experimentally accessible single-virtual direction, which directly leads to an estimate of the pion- and η -pole components of the muon g−2 . For the pion, our result for the g−2 contribution in the continuum is comparable with previous lattice and data-driven determinations, with combined relative uncertainties below 10% . For the η meson, we report on a preliminary determination from a single lattice spacing